Teses / dissertações: "Plasma immersion ion implantation"

1

Chen, Shou-Mian. "Plasma immersion ion implantation of silicon". Thesis, University of Surrey, 1997. http://epubs.surrey.ac.uk/842893/.

Texto completo da fonte

Resumo:

Plasma Immersion Ion Implantation has several unique advantages over conventional implantation, such as low cost, large area capability, non-line-of-sight features and high dose rate implantation. However, it is still far from use in routine production because of problems such as the ability to control the ion depth profile in targets, the ion dose and contamination. In this thesis, a PIII system has been systematically calibrated, and a computer simulation code for PIII has been developed in order to understand more clearly the physics of the PIII process and to optimise the experimental conditions. In the second part of this thesis, a new application of PIII has been explored, where the PIII technique has been used as a high dose-rate implant treatment to form amorphous silicon nitride/oxide films on both crystalline and amorphous silicon substrates. The electrical properties of these films have been characterized. It shows that low dose nitrogen/oxygen implantation leads to the modification of Schottky barrier heights or the introduction of charged defects in the materials. As the ion dose is increased, alloying effects take over, forming silicon nitride/oxide alloys. The a-SiNx:H films synthesized via PIII have electrical characteristics similar to those grown by PECVD, but a-SiOx:H has different electrical properties from a-SiNx:H.

Estilos ABNT, Harvard, Vancouver, APA, etc.

2

Allan, Scott Young. "Ion Energy Measurements in Plasma Immersion Ion Implantation". Thesis, The University of Sydney, 2009. http://hdl.handle.net/2123/5338.

Texto completo da fonte

Resumo:

This thesis investigates ion energy distributions (IEDs) during plasma immersion ion implantation (PIII). PIII is a surface modification technique where an object is placed in a plasma and pulse biased with large negative voltages. The energy distribution of implanted ions is important in determining the extent of surface modifications. IED measurements were made during PIII using a pulse biased retarding field energy analyser (RFEA) in a capacitive RF plasma. Experimental results were compared with those obtained from a two dimensional numerical simulation to help explain the origins of features in the IEDs. Time resolved IED measurements were made during PIII of metal and insulator materials and investigated the effects of the use of a metal mesh over the surface and the effects of insulator surface charging. When the pulse was applied to the RFEA, the ion flux rapidly increased above the pulse-off value and then slowly decreased during the pulse. The ion density during the pulse decreased below values measured when no pulse was applied to the RFEA. This indicates that the depletion of ions by the pulsed RFEA is greater than the generation of ions in the plasma. IEDs measured during pulse biasing showed a peak close to the maximum sheath potential energy and a spread of ions with energies between zero and the maximum ion energy. Simulations showed that the peak is produced by ions from the sheath edge directly above the RFEA inlet and that the spread of ions is produced by ions which collide in the sheath and/or arrive at the RFEA with trajectories not perpendicular to the RFEA front surface. The RFEA discriminates ions based only on the component of their velocity perpendicular to the RFEA front surface. To minimise the effects of surface charging during PIII of an insulator, a metal mesh can be placed over the insulator and pulse biased together with the object. Measurements were made with metal mesh cylinders fixed to the metal RFEA front surface. The use of a mesh gave a larger ion flux compared to the use of no mesh. The larger ion flux is attributed to the larger plasma-sheath surface area around the mesh. The measured IEDs showed a low, medium and high energy peak. Simulation results show that the high energy peak is produced by ions from the sheath above the mesh top. The low energy peak is produced by ions trapped by the space charge potential hump which forms inside the mesh. The medium energy peak is produced by ions from the sheath above the mesh corners. Simulations showed that the IED is dependent on measurement position under the mesh. To investigate the effects of insulator surface charging during PIII, IED measurements were made through an orifice cut into a Mylar insulator on the RFEA front surface. With no mesh, during the pulse, an increasing number of lower energy ions were measured. Simulation results show that this is due to the increase in the curvature of the sheath over the orifice region as the insulator potential increases due to surface charging. The surface charging observed at the insulator would reduce the average energy of ions implanted into the insulator during the pulse. Compared to the case with no mesh, the use of a mesh increases the total ion flux and the ion flux during the early stages of the pulse but does not eliminate surface charging. During the pulse, compared to the no mesh case, a larger number of lower energy ions are measured. Simulation results show that this is caused by the potential in the mesh region which affects the trajectories of ions from the sheaths above the mesh top and corners and results in more ions being measured with trajectories less than ninety degrees to the RFEA front surface.

Estilos ABNT, Harvard, Vancouver, APA, etc.

3

Allan, Scott Young. "Ion Energy Measurements in Plasma Immersion Ion Implantation". The School of Physics. The Faculty of Science, 2009. http://hdl.handle.net/2123/5338.

Texto completo da fonte

Resumo:

Doctor of Philosophy (PhD)
This thesis investigates ion energy distributions (IEDs) during plasma immersion ion implantation (PIII). PIII is a surface modification technique where an object is placed in a plasma and pulse biased with large negative voltages. The energy distribution of implanted ions is important in determining the extent of surface modifications. IED measurements were made during PIII using a pulse biased retarding field energy analyser (RFEA) in a capacitive RF plasma. Experimental results were compared with those obtained from a two dimensional numerical simulation to help explain the origins of features in the IEDs. Time resolved IED measurements were made during PIII of metal and insulator materials and investigated the effects of the use of a metal mesh over the surface and the effects of insulator surface charging. When the pulse was applied to the RFEA, the ion flux rapidly increased above the pulse-off value and then slowly decreased during the pulse. The ion density during the pulse decreased below values measured when no pulse was applied to the RFEA. This indicates that the depletion of ions by the pulsed RFEA is greater than the generation of ions in the plasma. IEDs measured during pulse biasing showed a peak close to the maximum sheath potential energy and a spread of ions with energies between zero and the maximum ion energy. Simulations showed that the peak is produced by ions from the sheath edge directly above the RFEA inlet and that the spread of ions is produced by ions which collide in the sheath and/or arrive at the RFEA with trajectories not perpendicular to the RFEA front surface. The RFEA discriminates ions based only on the component of their velocity perpendicular to the RFEA front surface. To minimise the effects of surface charging during PIII of an insulator, a metal mesh can be placed over the insulator and pulse biased together with the object. Measurements were made with metal mesh cylinders fixed to the metal RFEA front surface. The use of a mesh gave a larger ion flux compared to the use of no mesh. The larger ion flux is attributed to the larger plasma-sheath surface area around the mesh. The measured IEDs showed a low, medium and high energy peak. Simulation results show that the high energy peak is produced by ions from the sheath above the mesh top. The low energy peak is produced by ions trapped by the space charge potential hump which forms inside the mesh. The medium energy peak is produced by ions from the sheath above the mesh corners. Simulations showed that the IED is dependent on measurement position under the mesh. To investigate the effects of insulator surface charging during PIII, IED measurements were made through an orifice cut into a Mylar insulator on the RFEA front surface. With no mesh, during the pulse, an increasing number of lower energy ions were measured. Simulation results show that this is due to the increase in the curvature of the sheath over the orifice region as the insulator potential increases due to surface charging. The surface charging observed at the insulator would reduce the average energy of ions implanted into the insulator during the pulse. Compared to the case with no mesh, the use of a mesh increases the total ion flux and the ion flux during the early stages of the pulse but does not eliminate surface charging. During the pulse, compared to the no mesh case, a larger number of lower energy ions are measured. Simulation results show that this is caused by the potential in the mesh region which affects the trajectories of ions from the sheaths above the mesh top and corners and results in more ions being measured with trajectories less than ninety degrees to the RFEA front surface.

Estilos ABNT, Harvard, Vancouver, APA, etc.

4

Oates, Thomas William Henry. "Metal plasma immersion ion implantation and deposition using polymer substrates". Connect to full text, 2003. http://hdl.handle.net/2123/571.

Texto completo da fonte

Resumo:

Thesis (Ph. D.)--University of Sydney, 2004.
Title from title screen (viewed 5 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Physics, Faculty of Science. Degree awarded 2004; thesis submitted 2003. Includes bibliographical references. Also available in print form.

Estilos ABNT, Harvard, Vancouver, APA, etc.

5

Oates, T. W. H. "Metal plasma immersion ion implantation and deposition using polymer substrates". Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/571.

Texto completo da fonte

Resumo:

This thesis investigates the application of plasma immersion ion implantation (PIII) to polymers. PIII requires that a high negative potential be applied to the surface of the material while it is immersed in a plasma. This presents a problem for insulating materials such as polymers, since the implanting ions carry charge to the surface, resulting in a charge accumulation that effectively neutralises the applied potential. This causes the plasma sheath at the surface to collapse a short time after the potential is applied. Measurements of the sheath dynamics, including the collapsing sheath, are performed using an electric probe. The results are compared to theoretical models of the plasma sheath based on the Child-Langmuir law for high voltage sheaths. The theoretical model predicts well the sheath dynamics for conductive substrates. For insulating substrates the model can account for the experimental observations if the secondary electron coefficient is modified, justified on the basis of the poly-energetic nature of the implanting ions. If a conductive film is applied to the insulator surface the problem of charge accumulation can be avoided without compromising the effectiveness of PIII. The requirement for the film is that it be conductive, yet transparent to the incident ions. Experimental results are presented which confirm the effectiveness of the method. Theoretical estimates of the surface potential show that a film of the order of 5nm thickness can effectively circumvent the charge accumulation problem. Efforts to produce and characterise such a film form the final two chapters of this thesis. The optimal thickness is determined to be near the percolation threshold, where a marked increase in conductivity occurs. Spectroscopic ellipsometry is shown to be an excellent method to determine the film thickness and percolation threshold non-invasively. Throughout this work cathodic vacuum arcs are used to deposit thin films and as a source of metal plasmas. The design and construction of a pulsed cathodic vacuum arc forms a significant part of this thesis. Investigations of the cathode spots and power supply requirements are presented.

Estilos ABNT, Harvard, Vancouver, APA, etc.

6

Oates, T. W. H. "Metal plasma immersion ion implantation and deposition using polymer substrates". University of Sydney. Physics, 2003. http://hdl.handle.net/2123/571.

Texto completo da fonte

Resumo:

This thesis investigates the application of plasma immersion ion implantation (PIII) to polymers. PIII requires that a high negative potential be applied to the surface of the material while it is immersed in a plasma. This presents a problem for insulating materials such as polymers, since the implanting ions carry charge to the surface, resulting in a charge accumulation that effectively neutralises the applied potential. This causes the plasma sheath at the surface to collapse a short time after the potential is applied. Measurements of the sheath dynamics, including the collapsing sheath, are performed using an electric probe. The results are compared to theoretical models of the plasma sheath based on the Child-Langmuir law for high voltage sheaths. The theoretical model predicts well the sheath dynamics for conductive substrates. For insulating substrates the model can account for the experimental observations if the secondary electron coefficient is modified, justified on the basis of the poly-energetic nature of the implanting ions. If a conductive film is applied to the insulator surface the problem of charge accumulation can be avoided without compromising the effectiveness of PIII. The requirement for the film is that it be conductive, yet transparent to the incident ions. Experimental results are presented which confirm the effectiveness of the method. Theoretical estimates of the surface potential show that a film of the order of 5nm thickness can effectively circumvent the charge accumulation problem. Efforts to produce and characterise such a film form the final two chapters of this thesis. The optimal thickness is determined to be near the percolation threshold, where a marked increase in conductivity occurs. Spectroscopic ellipsometry is shown to be an excellent method to determine the film thickness and percolation threshold non-invasively. Throughout this work cathodic vacuum arcs are used to deposit thin films and as a source of metal plasmas. The design and construction of a pulsed cathodic vacuum arc forms a significant part of this thesis. Investigations of the cathode spots and power supply requirements are presented.

Estilos ABNT, Harvard, Vancouver, APA, etc.

7

Kosobrodova, Elena. "Plasma Immersion Ion Implanted Polymers for Antibody Microarray Applications". Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/13676.

Texto completo da fonte

Resumo:

A novel platform for protein microarrays with improved sensitivity and reproducibility was developed. Plasma immersion ion implantation (PIII) treated polycarbonate (PC) was used as a substrate for anti-cluster of differentiation (CD) antibody microarrays. Compared to the current industrial standard, nitrocellulose-coated glass slides, the novel platform requires a three times lower concentration of anti-CD antibodies to achieve an equivalent signal strength and has about two times better reproducibility and three times higher sensitivity. For the first time, an anti-CD antibody microarray was used to directly observe the reaction of living human white blood cells to foreign antibodies. It was shown that anti-CD antibody microarrays can be successfully used to test for patient specific cross-reactivity and hemotoxicity of therapeutic antibodies. To select the most suitable parameters of PIII treatment, the kinetics of free radicals formed in polystyrene (PS) during PIII treatment was studied. The rates of free radical decay were determined. Post-treatment oxidation of PIII treated PS has shown a close relationship of oxidation kinetics to the free radical kinetics. Both oxidation and hydrophobic recovery had two stages with characteristic times of several hours and several days. The time of PIII treatment of PC slides was selected taking into account protein binding capacity, wettability, surface chemistry and transparency of the PIII treated PC. The effect of untreated and PIII treated surfaces on the conformation and orientation of anti-CD34 antibody was studied. It was shown that the conformation of the antibody was better preserved on the PIII treated surface than on untreated one. Also, compared to untreated PC, a larger fraction of the antibody immobilized on PIII treated PC had an orientation optimal for antigen binding.

Estilos ABNT, Harvard, Vancouver, APA, etc.

8

Bozkurt, Bilge. "Dynamic Ion Behavior In Plasma Source Ion Implantation". Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607025/index.pdf.

Texto completo da fonte

Resumo:

The aim of this work is to analytically treat the dynamic ion behavior during the evolution of the ion matrix sheath, considering the industrial application plasma source ion implantation for both planar and cylindrical targets, and then to de-velop a code that simulates this dynamic ion behavior numerically. If the sepa-ration between the electrodes in a discharge tube is small, upon the application of a large potential between the electrodes, an ion matrix sheath is formed, which fills the whole inter-electrode space. After a short time, the ion matrix sheath starts moving towards the cathode and disappears there. Two regions are formed as the matrix sheath evolves. The potential profiles of these two regions are derived and the ion flux on the cathode is estimated. Then, by us-ing the finite-differences method, the problem is simulated numerically. It has been seen that the results of both analytical calculations and numerical simula-tions are in a good agreement.

Estilos ABNT, Harvard, Vancouver, APA, etc.

9

Tsoutas, Kostadinos Wallach. "Towards Advanced Bionics: Plasma Immersion Ion Implantation of Conductive Polypyrrole Films". Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/22624.

Texto completo da fonte

Resumo:

This thesis investigates the use of Plasma Immersion Ion Implantation (PIII) to modify electroploymerised polypyrrole (PPy) to allow for surface covalent binding of a range of biomolecules for biofunctionalized bionic applications. Synthesis regimes were investigated, aiming to produce PPy samples with the highest degree of batch consistency, chemical homogeneity and electroactivity. Galvanostatic samples at 0.2mA proved to produce superior PPy samples. PIII of nitrogen ions into PPy was modelled using TRIM/SRIM software. The depth of the treated volume of PPy was determined, along with the understanding of the atomic cascade into the PPy substrates. The modelling suggests that PIII of PPy will create an inhomogeneous treated volume with a composition that varies with depth. Surface carbonisation will occur as hydrogen atoms are recoiled or displaced. Changes in the composition and structure of PPy was investigated with a range of analytical techniques. PIII treatment of PPy was shown to produce a carbonised layer with increased carbon saturation. A threshold treatment time of between 40-80s is shown to exist, where any additional treatment beyond this amount has minimal impact on the composition and properties of PIII treated PPy. PIII treatment was shown to produce hydrophilic surfaces as a result of atomic reorganisation. A range of biological species were shown to be able to be covalently bound to PIII treated PPy. These include the ECM proteins tropoelastin and collagen I, the bioactive enzyme horseradish peroxidase, and the tropoelastin peptide fragment Pep36. Covalent binding was confirmed via use of SDS washing procedures. Conformation of the proteins and activity of the enzyme were shown to be maintained, as an outcome of the surface energy produced from treatment. The addition of ECM proteins to the treated surface were shown to increase the proliferation and binding of human dermal fibroblasts.

Estilos ABNT, Harvard, Vancouver, APA, etc.

10

Watkins, John H. "The application of plasma immersion ion implantation to sheep shearing combs /". Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phw335.pdf.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

11

Lui, So-ching, e 雷素青. "Surface bioactivity enhancement of polyetheretherketone (PEEK) by plasma immersion ion implantation". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43572340.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

12

Lui, So-ching. "Surface bioactivity enhancement of polyetheretherketone (PEEK) by plasma immersion ion implantation". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43572340.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

13

Michel, Thomas. "Développement de procédés d'implantation ionique par immersion plasma pour le photovoltaïque". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4307.

Texto completo da fonte

Resumo:

Le dopage du silicium par implantation ionique pour le photovoltaïque est une application relativement récente dont l'essor se heurte encore aujourd'hui aux coûts élevés d'intégration au sein des lignes de fabrication des cellules solaires. L'implantation ionique par immersion plasma promet de répondre aux futures exigences du secteur en termes de coûts et de productivité.Ces travaux de thèse ont permis le développement de procédés d'implantation ionique par immersion plasma de l'équipement PULSION®, conçu par IBS, dédiés à la fabrication de cellules solaires en silicium monocristallin. Dans un premier temps, nous montrons qu'il permet la réalisation de profils de dopage d'émetteur de type n variés, répondant aux exigences des cellules solaires à haut rendement. Les émetteurs fabriqués sont caractérisés de manière chimique, physique et électrique afin de démontrer leur excellente qualité. L'intégration de l'implantation ionique des émetteurs au sein d'un processus de fabrication industriel et peu coûteux, développé par l'INES sur silicium monocristallin de type p, permet d'atteindre des rendements de conversion supérieurs à 19,3%, soit un gain de plus de 0,5% par rapport aux rendements obtenus avec des cellules usuelles à émetteurs dopés par diffusion POCl3.La réalisation d'émetteurs de type p est également étudiée dans ce mémoire afin de préparer la transition technologique vers les cellules solaires sur silicium monocristallin de type n. Confirmant les atouts et le potentiel de la technologie d'implantation ionique par immersion plasma, les travaux menés au cours de cette thèse débouchent sur la conception d'un prototype industriel PULSION® dédié au photovoltaïque
Ion implantation is a major process technology for manufacturing integrated circuits. However, silicon doping by ion implantation for photovoltaics is a relatively recent application, and its growth still faces high costs of integration into solar cell production lines. Plasma-immersion ion implantation (PIII) promises to meet the future industry requirements in terms of costs and productivity.This thesis work has led to the development of processes dedicated to silicon-based solar cell manufacturing using the plasma-immersion ion implanter – PULSION® – designed by IBS. First, we show that PIII enables the realization of various doping profiles for phosphorus-doped emitters which fit the requirements of high-efficiency solar cells. Emitters thus fabricated are chemically, physically and electrically characterized to demonstrate their excellent quality. Those emitters, implanted through plasma immersion and integrated into a low cost solar cell manufacturing line from INES on monocrystalline silicon, enable to raise the conversion efficiency, obtained with conventional POCl3-diffused solar cells, by more than 0.5% absolute to reach efficiencies above 19.3%.Fabrication of p-type boron implanted emitters is also studied in order to improve conversion efficiencies of p-type silicon based solar cells, but also in order to anticipate the technological shift from p-type to n-type silicon material. Thanks to this thesis work, the strength and potential of PIII for photovoltaic applications have been proven and this has convinced IBS to design a PULSION® equipment dedicated to solar cell manufacturing

Estilos ABNT, Harvard, Vancouver, APA, etc.

14

Ho, Joan Pui Yee. "Plasma Surface Modification of Biomedical Polymers and Metals". Thesis, The University of Sydney, 2007. http://hdl.handle.net/2123/2463.

Texto completo da fonte

Resumo:

Biomedical materials are being extensively researched, and many different types such as metals, metal alloys, and polymers are being used. Currently used biomedical materials are not perfect in terms of corrosion resistance, biocompatibility, and surface properties. It is not easy to fabricate from scratch new materials that can fulfill all requirements and an alternative approach is to modify the surface properties of current materials to cater to the requirements. Plasma immersion ion implantation (PIII) is an effective and economical surface treatment technique and that can be used to enhance the surface properties of biomaterials. The unique advantage of plasma modification is that the surface properties and functionalities can be enhanced selectively while the favorable bulk attributes of the materials such as strength remain unchanged. In addition, the non-line of sight feature of PIII is appropriate for biomedical devices with complex geometries such as orthopedic implants. However, care must be exercised during the plasma treatment because low-temperature treatment is necessary for heat-sensitive materials such as polymers which typically have a low melting point and glass transition temperature. Two kinds of biomedical materials will be discussed in this thesis. One is nickel titanium (NiTi) alloy which is a promising orthopedic implant material due to its unique shape memory and superelastic properties. However, harmful ions may diffuse from the surface causing safety hazards. In this study, we investigate the properties and performance of NiTi after nitrogen and oxygen PIII in terms of the chemical composition, corrosion resistance, and biocompatibility. The XPS results show that barrier layers mainly containing TiN and TiOx are produced after nitrogen and oxygen PIII, respectively. Based on the simulated in vitro and electrochemical corrosion tests, greatly reduced ion leaching and improved corrosion resistance are accomplished by PIII. Porous NiTi is also studied because the porous structure possesses better bone ingrowth capability and compatible elastic modulus with human bones. These advantages promote better recovery in patients. However, higher risks of Ni leaching are expected due to the increased exposed surface area and rougher topography than dense and smooth finished NiTi. We successfully apply PIII to porous NiTi and in vitro tests confirm good cytocompatibility of the materials. The other type of biomedical materials studied here is ultra-high molecular weight polyethylene (UHMWPE) which is a potential material for use in immunoassay plates and biosensors. In these applications, active antibodies or enzymes attached to a surface to detect molecules of interests by means of specific interactions are required. Moreover, the retention of enzyme activity is crucial in these applications. Therefore, the aim of this study is to investigate the use of PIII to prepare UHMWPE surfaces for binding of active proteins in terms of the binding density and ‘shelf life’ of the treated surfaces. Argon and nitrogen PIII treatments are attempted to modify the surface of UHMWPE. Horseradish peroxidase (HRP) is selected to conduct the protein binding test since it is a convenient protein to assay. Experimental results show that both PIII treated surfaces significantly improve the density of active HRP bound to the surface after incubation in buffer containing HRP. Furthermore, the PIII treated surfaces are found to perform better than a commercially available protein binding surface and the shelf life of the PIII treated surfaces under ambient conditions is at least six months. In conclusion, a biocompatible barrier layer on NiTi and a protein binding surface on UHMWPE is synthesized by PIII. The surface properties such as corrosion resistance and functionality on these two different types of substrates are improved by PIII.

Estilos ABNT, Harvard, Vancouver, APA, etc.

15

Ho, Joan Pui Yee. "Plasma Surface Modification of Biomedical Polymers and Metals". University of Sydney, 2007. http://hdl.handle.net/2123/2463.

Texto completo da fonte

Resumo:

Doctor of Philosophy(PhD)
Biomedical materials are being extensively researched, and many different types such as metals, metal alloys, and polymers are being used. Currently used biomedical materials are not perfect in terms of corrosion resistance, biocompatibility, and surface properties. It is not easy to fabricate from scratch new materials that can fulfill all requirements and an alternative approach is to modify the surface properties of current materials to cater to the requirements. Plasma immersion ion implantation (PIII) is an effective and economical surface treatment technique and that can be used to enhance the surface properties of biomaterials. The unique advantage of plasma modification is that the surface properties and functionalities can be enhanced selectively while the favorable bulk attributes of the materials such as strength remain unchanged. In addition, the non-line of sight feature of PIII is appropriate for biomedical devices with complex geometries such as orthopedic implants. However, care must be exercised during the plasma treatment because low-temperature treatment is necessary for heat-sensitive materials such as polymers which typically have a low melting point and glass transition temperature. Two kinds of biomedical materials will be discussed in this thesis. One is nickel titanium (NiTi) alloy which is a promising orthopedic implant material due to its unique shape memory and superelastic properties. However, harmful ions may diffuse from the surface causing safety hazards. In this study, we investigate the properties and performance of NiTi after nitrogen and oxygen PIII in terms of the chemical composition, corrosion resistance, and biocompatibility. The XPS results show that barrier layers mainly containing TiN and TiOx are produced after nitrogen and oxygen PIII, respectively. Based on the simulated in vitro and electrochemical corrosion tests, greatly reduced ion leaching and improved corrosion resistance are accomplished by PIII. Porous NiTi is also studied because the porous structure possesses better bone ingrowth capability and compatible elastic modulus with human bones. These advantages promote better recovery in patients. However, higher risks of Ni leaching are expected due to the increased exposed surface area and rougher topography than dense and smooth finished NiTi. We successfully apply PIII to porous NiTi and in vitro tests confirm good cytocompatibility of the materials. The other type of biomedical materials studied here is ultra-high molecular weight polyethylene (UHMWPE) which is a potential material for use in immunoassay plates and biosensors. In these applications, active antibodies or enzymes attached to a surface to detect molecules of interests by means of specific interactions are required. Moreover, the retention of enzyme activity is crucial in these applications. Therefore, the aim of this study is to investigate the use of PIII to prepare UHMWPE surfaces for binding of active proteins in terms of the binding density and ‘shelf life’ of the treated surfaces. Argon and nitrogen PIII treatments are attempted to modify the surface of UHMWPE. Horseradish peroxidase (HRP) is selected to conduct the protein binding test since it is a convenient protein to assay. Experimental results show that both PIII treated surfaces significantly improve the density of active HRP bound to the surface after incubation in buffer containing HRP. Furthermore, the PIII treated surfaces are found to perform better than a commercially available protein binding surface and the shelf life of the PIII treated surfaces under ambient conditions is at least six months. In conclusion, a biocompatible barrier layer on NiTi and a protein binding surface on UHMWPE is synthesized by PIII. The surface properties such as corrosion resistance and functionality on these two different types of substrates are improved by PIII.

Estilos ABNT, Harvard, Vancouver, APA, etc.

16

Lee, Shih-Liang. "Plasma-based modifications of synthetic vascular grafts". Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/24373.

Texto completo da fonte

Resumo:

Current clinically available synthetic vascular grafts are made from either polyethylene terephthalate (PET) or expanded polytetrafluoroethylene (ePTFE). In small diameter applications less than 6 mm, these materials are prone to high failure rates caused acutely by blood clot formation and in the mid-term by inflammatory-driven neointimal hyperplasia. A key driver of these modes of graft failure is the slow regeneration of the protective endothelial layer that lines the surface of blood vessels, impaired by the highly hydrophobic polymer surfaces and lack of appropriate biological cues. Surface modifications and presentation of targeted biomolecular cues which promote endothelialisation could address these issues. Identification of the right combination of surface treatment and selection of appropriate cues has proven to be challenging thus far. This thesis explores two different plasma-based modifications of synthetic vascular grafts, to promote rapid endothelialisation. The outcomes of bioengineered grafts were tested under in vitro and in vivo models. Overall, this thesis has demonstrated rapid endothelialisation in two novel synthetic vascular grafts, employing different surface modifications and biomolecules. These findings suggest that both of these approaches have significant potential, justifying further pre-clinical evaluation in the future.

Estilos ABNT, Harvard, Vancouver, APA, etc.

17

Kouadri, Boudjelthia El Amin. "Piégeage des impuretés métalliques présentes dans le silicium destiné au photovoltaïque par plasma immersion ion implantation (PIII)". Thesis, Orléans, 2012. http://www.theses.fr/2012ORLE2089.

Texto completo da fonte

Resumo:

Malgré son grand potentiel, l’énergie photovoltaïque n’arrive pas encore à trouver une grande place dans le paysage énergétique mondial. Elle se heurte à deux problèmes de taille : le coût et le rendement. Les cellules solaires à base du silicium multicristallin (mc-Si) perdent beaucoup de leur rendement à cause de la présence des impuretés métalliques. Plusieurs recherches ont montré que les cavités induites par implantation ionique sont efficaces dans le piégeage des impuretés. Mais les techniques utilisées dans l’implantation n’ont pas permis à ce procédé de se développer dans l’industrie à cause de leur coût élevé. Le plasma immersion ion implantation (PIII) est une technique bas coût qui permet d’implanter de grandes surfaces. Elle est utilisée dans le traitement de surface à l’échelle industrielle, mais à ce jour aucune étude n’a montré son utilisation dans le piégeage des impuretés dans le silicium. Dans cette thèse nous avons créé des cavités dans le mc-Si par implantation d’hydrogène par PIII. Plusieurs techniques de caractérisation ont été utilisées afin d’étudier le mécanisme de formation de ces cavités. La MET, la photoluminescence et les positons ont été utilisées pour avoir un maximum d’informations sur la nature et l’évolution des défauts créés par implantation d’hydrogène. Nous avons également étudié la différence entre les cavités formées par PIII et celles formées par implantation classique. Les cavités formées ont été utilisées, par la suite, pour le piégeage des impuretés métalliques présentes dans le mc-Si (Cu, Fe, Cr et Ni). Les résultats obtenus par SIMS ont monté l’efficacité de notre procédé dans le piégeage des impuretés métalliques
Extraction of silicon metal impurities to be used for photovoltaic by plasma immersion ion implantation (PII)

Estilos ABNT, Harvard, Vancouver, APA, etc.

18

Motloung, Setumo Victor. "Intense pulsed neutron generation based on the principle of Plasma Immersion Ion Implantation (PI3) technique". Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_9599_1182748458.

Texto completo da fonte

Resumo:

The development of a deuterium-deuterium/ tritium-deuterium (D-D/ D-T) pulsed neutron generator based on the principle of the Plasma Immersion Ion Implantation (PI3) technique is presented, in terms of investigating development of a compact system to generate an ultra short burst of mono-energetic neutrons (of order 1010 per second) during a short period of time (<
20&mu
s) at repetition rates up to 1 kHz. The system will facilitate neutron detection techniques, such as neutron back-scattering, neutron radiography and time-of-flight activation analysis.

Aspects addressed in developing the system includes (a) characterizing the neutron spectra generated as a function of the target configuration/ design to ensure a sustained intense neutron flux for long periods of time, (b) the system was also characterised as a function of power supply operating conditions such as voltage, current, gas pressure and plasma density.

Estilos ABNT, Harvard, Vancouver, APA, etc.

19

Chong, Yu-wah, e 莊瑜華. "In vitro and in vivo study of plasma immersion ion implantation (PIII)treated polyetheretherketone (PEEK)". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B4985883X.

Texto completo da fonte

Resumo:

Polyetheretherketone (PEEK), a polymer with mechanical strength comparable to human bone, is gaining popularity in the orthopedic field because it can potentially relieve the clinical complications, such as stress shielding effect and inevitable implantation failure, which are caused by the mismatch of the mechanical strength between the current metallic implants and the implantation sites. However, it is bio-inert and requires supplementary modification. Plasma immersion ion implantation (PIII) has been well documented that it is a good way to improve the bioactivity of a biomaterial. It is a method that introduces new elements to the biomaterial, generating bio-functional groups on the material surface without altering its mechanical properties. Hence, the aim of this study is to improve the bioactivity of PEEK by modifying its surface chemistry with the use of water (H2O) and ammonia (NH3) plasma immersion ion implantation (PIII) without altering its mechanical properties. After PIII treatment, a series of surface characterization tests that provide information about the surface properties, such as surface energy, roughness, surface chemical composition and crystallinity of PIII-treated PEEK were carried out. Results show that both H2O PIII and NH3 PIII-treated PEEK had significantly higher surface energy and roughness than untreated PEEK. There was also no significant change in the crystallinity of the PIII-treated PEEK, indicating that PIII treatment will not alter the mechanical properties of PEEK. Improvement in wetting properties of PEEK samples suggest the formation of polar functional groups on the PIII-treated PEEK materials, while the increased in surface roughness may be due to the energetic bombardments of plasma ions on the material surface. The in vitro bioactivity of plasma-treated PEEK was investigated and confirmed with hMSC-TERT. Initial cell attachment, cell spreading area, cell proliferation and differentiation were studied. Cell adhesion and cell spreading were enhanced on PIII-treated PEEK, and higher cell viability was observed on PIII-treated PEEK. Moreover, cell proliferation was promoted on early time point and cell differentiation was also enhanced particularly on day 7 by measuring the alkaline phosphatase activity. Therefore, H2O-PIII and NH3-PIII treatments were able to promote the bioactivity of PEEK samples.
published_or_final_version
Orthopaedics and Traumatology
Master
Master of Philosophy

Estilos ABNT, Harvard, Vancouver, APA, etc.

20

Tran, Clara. "Plasma activated polymers for yeast and enzyme immobilization". Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10127.

Texto completo da fonte

Resumo:

This thesis investigates plasma immersion ion implantation (PIII) for immobilizing enzymes and yeast cells with the aim of developing new processes for cellulosic ethanol production. A rapid and effective immobilization of yeast cells was demonstrated on PIII treated polymer surfaces. The immobilization does not inhibit the ability of yeast cells to produce ethanol. A model was developed to describe the different mechanisms of rehydrated yeast attachment to untreated and PIII treated surfaces. Yeast cells attach to the untreated surface by hydrophobic interactions while they attach to the PIII treated surface by covalent bonds. The immobilization of yeast cells on the PIII treated surface was found to greatly enhance their resistance to shear forces. In low ionic strength solution, pH was found to be a control factor for the immobilization through the effect of surface and molecule charges. Acidic buffers (pH 3-5) facilitate the immobilization on the PIII treated surface while alkaline buffers (pH 6-10) prevent it. Allylamine exposure was demonstrated to reduce the negative charge of the PIII treated surface in solution and thereby improve the yeast attachment. CelB, an enzyme which has both endo- and exo-glucanase activities, was covalently immobilized on a PIII treated polymer. Immobilized celB shows the Arrhenius behaviour of the activity as a function of temperature. Approximately 70% of the immobilized celB activity was retained after 4 usage cycles. When used together with immobilized ß-glucosidase, immobilized celB activity is enhanced. A simultaneous saccharification and fermentation process using immobilized enzymes (celB and ß-glucosidase) and immobilized yeast cells under a flow regime was demonstrated to illustrate the potential of using this immobilization technique in continuous flow processes with increased utilisation of expensive enzymes.

Estilos ABNT, Harvard, Vancouver, APA, etc.

21

Jaichuen, C., R. Chundet, L. D. Yu, P. Thongkumkoon e S. Anuntalabhochai. "Effect on Genetic Mutation Induction from Nano-Ranged Low-Energy Plasma Ion Bombardment of DNA and Gene Fragment". Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34948.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

22

Maury, Mathieu. "Simulation numérique de la fragmentation d'un précurseur de dopage au sein d'un réacteur d'implantation ionique par immersion plasma". Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCD057/document.

Texto completo da fonte

Resumo:

Cette thèse est centrée sur le développement de modèles numériques pour simuler le comportement physique des plasmas présents dans un réacteur d'implantation ionique à immersion plasma. Ces modèles ont pour but d'estimer l'impact des réglages opérationnels du réacteur sur les paramètres plasma pertinents pour l'implantation, comme le flux ionique sur le substrat et la distribution en énergie des ions. La géométrie complexe du réacteur rend difficile sa modélisation d'un seul tenant, du fait des importants gradients temporels et spatiaux attendus pour les densités ioniques et la température électronique. Une stratégie de simulation en deux étapes a donc été adoptée : - Un modèle quasi-homogène, couplé à un module de chimie en volume élaboré, permet de représenter des deux portions de la source plasma et d'obtenir l'évolution de la composition du plasma en fonction de la puissance radiofréquence injectée. - Un modèle unidimensionnel de type PIC-MC permet de décrire la dynamique de la gaine ionique qui se forme près du substrat du fait du potentiel imposé, ainsi que de déterminer la distribution de l'énergie d'impact des ions et les flux d'implantation correspondants. Au final, ces travaux de recherche ont permis d'aboutir à une meilleure compréhension de l'impact des paramètres opérationnels du réacteur sur le flux ionique et la distribution en énergie des ions arrivant sur le substrat. La connaissance des couplages physiques entre la source plasma et la chambre d'implantation autorise l'optimisation du processus de dopage, puisque les paramètres opérationnels peuvent être réglés de manière à minimiser la profondeur de dopage après implantation
Numerical models have been developped to simulate the plasma present inside a plasma immersion ion implantation reactor. Their goal is to estimate the impact of the reactor’s settings on the plasma parameters relevant for ion implan-tation. The complex geometry of the reactor renders its modelling difﬁcult, because of the stiff spatial and temporal gradients expected, so a two-step simulation stra-tegy was adopted : – A global model of the plasma source, coupled to a detailed volume chemistry module, allows to determine the time evolution of the plasma composition according to the radio-frequency power injected in the source.– A 1D PIC-MC model of the sheath facing the substrate describes the dyna-mics of the expanding sheath and allows to determine the ion impact energy distribution function and corresponding implantation proﬁles. Determination of the couplings between the plasma source and the implantation chamber makes possible to optimize the doping process, since the reactor’s opera-tional settings can then be adjusted to minimize the doping depth after implanta-tion

Estilos ABNT, Harvard, Vancouver, APA, etc.

23

Cheng, Xinying. "Shape Memory Polymers with Multifaceted Tunability and Bio-specificity". Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17130.

Texto completo da fonte

Resumo:

Shape memory polymers (SMP) have been of great interest in biomedical applications due to their unique ability to recover a primary shape by external actuation. Shape memory polyurethanes (SMPU) have also been widely studied as implant biomaterials, benefiting from the opportunity to create dual-shape, compliant, and durable materials. However, SMPU still suffer from the lack of mechanical properties and a failure to tune their biological interface prior to implantation. In this study, SMPU and carbon fibre (CF) reinforced composites for implantable biomaterials were developed, and their mechanical properties and biocompatibility were comprehensively characterised. The addition of CF in SMPU shows the improved mechanical properties, and CF in CF/SMPU played a reinforcement or resistance role in shape memory recovery rate above or below Tg, while the shape recovery force of CF/SMPU was enhanced significantly. PIII surface modification improved the wettability of SMPU and other surface properties, without affecting bulk properties. PIII treatment duration determined the degree of surface changes, and the SMPU surface with PIII treatment for 200 seconds resulted in a saturated level of covalently immobilised collagen. Implanted SMPU45 with PIII treatment and collagen coating shows good performance in biocompatibility. The results of histology and immunohistochemistry showed less acute and subacute immune response to PIII treated + collagen coated SMPU45 than the mock treated ones, suggesting a better wound healing ability. It has been demonstrated that SMPU45 is a promising biomaterial with functional properties of shape memory effect. Applying the PIII surface modification combined with protein attachment enables SMPU45 to improve host compatibility by minimizing biological limitations, and will enhance the performance of SMPU devices for various implant biomedical applications in the future.

Estilos ABNT, Harvard, Vancouver, APA, etc.

24

Urbonavičius, Marius. "Titano okisdų formavimas vandens garų plazmoje". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120202_132623-41801.

Texto completo da fonte

Resumo:

Šio darbo literatūros apžvalgoje aptariami plazmos tipai, plazmos charakteristikos bei sąveika su medžiaga. Aptariama plazminės implantacijos technologija. Trumpai apibūdinama vandens garų plazma ir jos panaudojimas. Apžvelgiama titano oksido struktūra bei jo panaudojimas katalizatorių gamybai, kurie gali būti skirti skaldyti vandens molekules ir gaminti vandenilį. Darbe paaiškinamas magnetroninis nusodinimas bei jo privalumai. Darbo metu buvo oksiduojamas titanas vandens garų plazmoje. Titano oksidacija priklauso nuo daugybės plazmoje vykstančių procesų (adsorbcija, sulaikymas, vakansijų susidarymas ir pan.). Titano oksido panaudojimas yra labai platus dabartiniu metu. Aptariama šio eksperimento technologija bei atliekama oksiduotų titano dangų analizė. SEM, XRD, AES, GDOES analizės metodais buvo tiriama titano dangos oksidacija ir aiškinamas oksidacijos mechanizmas.
Types of plasma, characteristics and plasma interaction with solids are discussed in the literature review of this paper. Also, the plasma immersion ion implantation are described. Water vapour plasma are briefly discussed. Titanium oxide structure and it‘s usage for catalyst which could split water molecules are reviewed. Magnetron deposition are explained in this paper. The titanium film was oxidized by water vapour plasma on experiment. The oxidation of titanium depends on many processes in plasma (adsorption, trapping, formation of oxygen vacancies and etc.). Appliance of titanium oxide is very large in recent times. Experimental technology are discussed and plasma treated films are analysed. Titanium oxidation was analysed by SEM, XRD, AES, GDOES. Oxidation mechanism was explained in this paper.

Estilos ABNT, Harvard, Vancouver, APA, etc.

25

Kaeppelin, Vincent. "Caractérisation d'une source de plasma hélicon et application à l'implantation ionique par immersion plasma". Aix-Marseille 1, 2002. http://www.theses.fr/2002AIX11027.

Texto completo da fonte

Resumo:

Cette thèse a porté sur l'étude d'une source de plasma de type hélicon et sur l'implantation ionique par immersion plasma (IIIP). La caractérisation du réacteur s'est faite dans des plasmas d'argon à l'aide d'une sonde de Langmuir, et d'un spectromètre de masse, doté d'un secteur d'analyse en énergie. Suivant les valeurs de puissance injectée, pression de gaz et champ magnétique, trois modes de couplage distincts ont été mis en évidence : un couplage capacitif à faible puissance avec des densités comprises entre 10[9] et 10[10] cm[-3], puis avec une puissance plus élevée, un couplage inductif avec une augmentation de la densité (10[10]-10[11] cm[-3]) et enfin, à forte puissance (> 1 kW), une onde hélicon peut être excitée par l'antenne et participer à une ionisation en volume du plasma (densité entre 10[11] et 10[12] cm[-3]). Un travail sur les plasmas pulsés est également présenté dans ce mémoire. Ces valeurs de densités élevées pour des plasmas à basse pression (< 5 [mu]Bar) peuvent s'avérer particulièrement intéressantes pour des procédés de micro électronique, et en particulier pour l'IIIP. Ainsi, la société IBS, spécialisée dans l'implantation ionique, développe depuis quelques années un procédé d'IIIP et afin de l'améliorer, a souhaité adapter une source de plasma radiofréquence sur son prototype. La caractérisation du nouveau réacteur a été faite dans des plasmas d'azote et de trifluorure de bore (BF3). Nous avons ainsi montré une augmentation de la densité de un à deux ordres de grandeurs, suivant la valeur de puissance injectée, par rapport à la configuration initiale. Désormais, une large gamme de densités est accessible (10[7] à 10[10] cm[-3]). Une étude de la composition chimique des plasmas a également été réalisée. Des implantations de bore ont été effectuées à l'aide de ce procédé pour réaliser des cellules solaires. Les analyses SIMS de ces cellules ont montré la formation de jonctions ultra-fines, qui doivent permettre d'améliorer le rendement des photopiles

Estilos ABNT, Harvard, Vancouver, APA, etc.

26

Katsifis, Georgio Andrew. "Analysis and Characterisation of Plasma Treated PEEK Scaffolds and their Implementation in Radiotherapy". Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29503.

Texto completo da fonte

Resumo:

Bone sarcomas are a present as tumours which occur in bones and soft tissues. Bone must often be removed during the treatment of these cancers and a replacement bone scaffold must be implanted to heal and bridge the removed tissue. Titanium stands as the most popular implant as a general orthopaedic implant due to its impressive mechanical properties and bio-compatibility. However, the high stiffness also poses problems due to the material mismatch with bone and can cause aseptic loosening at the interface, potentially leading to implant failure. In radiotherapy, titanium perturbs radiation beams and compromises both radiotherapy and imaging beams as well as damaging the osseointegrating cells. Our solution is to 3D print scaffolds out of Poly-ether-ether-ketone (PEEK), a biocompatible polymer already used in orthopaedics.

Estilos ABNT, Harvard, Vancouver, APA, etc.

27

Duchaine, Julian. "Caractérisation de l'implantation par immersion plasma avec pulsion(r) et intégration dans la fabrication de transistors FD-SOI et Trigate". Toulouse 3, 2012. http://www.theses.fr/2012TOU30197.

Texto completo da fonte

Resumo:

L'industrie de la micro-électronique remet à jour régulièrement sa " roadmap " internationale pour ses développements technologiques. L'introduction des nouvelles filières technologiques s'accélère, motivée par les besoins en électronique portable, en ordinateurs personnels de plus en plus puissants, en télécommunications et multimédia, ainsi que par le développement maintenant très important de l'électronique dans le monde de l'automobile. Cette course à l'intégration nécessite des implantations à des énergies de plus en plus faibles et des doses de plus en plus fortes (en fonction des composants). Afin de répondre à la demande des industriels du domaine de la microélectronique, IBS a conçu son propre prototype d'implanteur ionique par immersion plasma (PULSION(r)). Ce type d'implantation est très attractif pour les industriels car il offre un rendement et des cadences de production (wafer/heure) plus importants avec un coût de fabrication plus faible qu'un implanteur dit classique (faisceau d'ions). Cette thèse a pour but de caractériser les procédés d'implantation de type P par immersion plasma de manière approfondie en utilisant la machine PULSION installée au LETI afin de les intégrer dans la fabrication de composants dernières générations (FD-SOI ultime et Trigate pour nano-fils). De nombreuses études expérimentales ont été réalisées afin de comprendre les mécanismes physiques et chimiques mis en jeu lors de l'implantation par immersion plasma. La compréhension de ces mécanismes est beaucoup plus compliquée qu'une implantation par faisceau d'ions car le substrat est constamment immergé dans un plasma et toutes les espèces ioniques du plasma sont implantées. Nous avons donc observé des comportements différents des profils implantés entre les deux techniques d'implantation. Les conditions de plasma ont ensuite été optimisées dans le but d'intégrer les procédés Pulsion(r) dans la fabrication de transistors FD-SOI et Trigate. Les premiers résultats montrent que l'implantation par immersion plasma permet d'obtenir sur des composants planaires (FD-SOI) les mêmes performances électriques qu'un implanteur à faisceau d'ions. Par contre les performances sont nettement améliorées sur des transistors multi-grilles de type Trigate. Des développements procédés devraient encore améliorer ses performances
The industry of microelectronics will update regularly its "roadmap" for its international technological developments. The development of new technological processes is accelerating, driven by the need for portable electronics, personal computers with more powerful, telecommunications and multimedia, as well as the very important development of electronics in the automobile world. This race requires the integration of implantation processes with low energy and high dose (based on components). To meet the demand of industrial, IBS has developed its own prototype of plasma immersion ion implanter (PULSION (r)). This type of tool is very attractive to manufacturers because it offers performance and production rates (wafer / hour) with a lower manufacturing cost than conventional implanter (ion beam). This thesis aims to characterize the processes of P-type implantation by plasma immersion using the tool installed at the LETI "PULSION "to integrate in the manufacture of new transistors generations (FD-SOI ultimate Trigate for nano-wires). Many experimental studies have been performed to understand the physical and chemical mechanisms involved during the plasma immersion implantation. Understanding these mechanisms is much more complicated than ion beam implantation because the substrate is constantly immersed in the plasma and all ion species are implanted into the substrate. So, we observed different behavior of the implanted boron atoms between the two implantation techniques. The plasma and implantation conditions were optimized in order to integrate Pulsion (r) processes in the manufacture of FD-SOI and Trigate transistors. The first results show that plasma immersion implantation provides, on planar components (FD-SOI), the same electrical performance as ion beam implanter. Against by performance improved significantly on Trigate transistors. Further developments processes should improve again its performance

Estilos ABNT, Harvard, Vancouver, APA, etc.

28

Barakel, Damien. "Implantations d'ions H+ et BF2+ dans du silicium par faisceau et immersion plasma. Application aux cellules solaires". Aix-Marseille 3, 2004. http://www.theses.fr/2004AIX30065.

Texto completo da fonte

Resumo:

La technique d'implantation d'ions par faisceau est actuellement bien maîtrisée dans le silicium. Elle pourrait être remplacée par l'immersion dans un plasma. Dans ce travail nous examinons les effets de l'implantation à forte dose d'ions hydrogène par les deux techniques précédentes ainsi que la formation de jonctions P+-N par un plasma de BF3. Nous montrons que l'hydrogène peut former des donneurs peu profonds et que du silicium de type P est converti en type N, au voisinage de la surface implantée, à une profondeur correspondant au parcours projeté. Des plaquettes de silicium multicristallin ont été améliorées par immersion dans un plasma d'hydrogène, par suite de la passivation des imperfections volumiques. Des jonctions très peu profondes peuvent être obtenues par dopage par immersion dans un plasma de faible énergie. Des cellules solaires ont été préparées en utilisant les deux techniques d'implantation
Ion beam implantation technique is currently used in silicon technology, however it could be replaced by plasma immersion ion implantation. In this work we investigate the effects of a heavy hydrogen ion dose implantation by both preceding techniques, as well as the formation of P+-N junctions by BF3 plasma ion immersion. We have found that hydrogen can form shallow donors and that P type silicon can be converted in N type, close to the surface, at a depth corresponding to the projected range. Multicrystalline silicon wafers were improved after hydrogen plasma immersion, due to the passivation of bulk imperfections. Ultra shallow junctions can be obtained by plasma immersion doping at low energy. Solar cells have been prepared using both techniques

Estilos ABNT, Harvard, Vancouver, APA, etc.

29

Vervisch, Vanessa. "Etude et réalisation de jonctions ultra fines P+N par la technique d'implantation d'ions par immersion plasma. Application aux cellules photovoltaïques". Aix-Marseille 3, 2007. http://www.theses.fr/2007AIX30065.

Texto completo da fonte

Resumo:

Ce travail présente la technique d'implantation d'ions par immersion plasma (PIII) comme un outil prometteur pour la réalisation des jonctions ultra fines (USJ). Le prototype PIII appelé PULSION® utilisé dans cette étude, a été conçu et développé par la société IBS. Les profils SIMS de bore obtenus sur des échantillons implantés par PULSION® montrent des profondeurs d'implantation variant de quelques nanomètres à une trentaine de nanomètres avant activation. Ces résultats nous ont amené à concentrer nos efforts sur l'optimisation des recuits d'activation post implantation afin d'obtenir le meilleur compromis X/Rsq. Différents recuits tels que le RTA, le Spike et le LASER ont ensuite été associés à l'implantation PIII et comparés entre eux. Les caractérisations électriques et physico-chimiques présentent le recuit laser comme une technologie prometteuse associée à l'implantation PIII. Afin de limiter l'effet de canalisation des atomes de bore lors des implantations PIII, plusieurs pré-amorphisations (PAI) ont été étudiées. Parmi elles, la PAI d'ions germanium montre des résultats intéressants. L'amorphisation du silicium (estimée à 20 nm à partir d'imagerie TEM) permet de diminuer la profondeur de jonction de 30 nm à 24 nm après activation. Une application de la technique PIII à la conception de l'émetteur d'une photodiode a été effectuée. Les caractéristiques électriques du composant ainsi réalisé sont comparables à des cellules standards. De plus, la faible épaisseur de la jonction permet une amélioration du rendement quantique interne dans les courtes longueurs d'onde, ce qui permettrait l'utilisation de telles cellules dans le domaine spatial
This study describes the plasma immersion ion implantation as a potential tool in order to realize ultra shallow junctions (USJ). The PIII prototype called PULSION® used in this work has been designed and developed by IBS Company. Boron SIMS profiles obtained on PULSION® as-implanted samples reveal implantation depths varying from few nanometers up to thirty nanometers. These results led us to focus on post implantation annealings in order to obtain the best compromise between junction depth (Xj) and sheet resistance (Rsq). Different annealing techniques such as RTA, Spike and LASER have been processed and compared after PIII. Electrical and physico-chemical characterisations set forth the laser annealing process. The Pre-Amorphization Implantation (PAI) has been implemented in order to reduce the channelling effect. The best results were obtained with germanium ions. The amorphized silicon with a thickness estimated to 20 nm according to TEM pictures, appeared to cause a decreasing of the junction depth from 30 to 24 nm after annealing. PIII technology was applied to the conception of photodiode emitters. Electrical properties of the realized device revealed to be satisfactory. Moreover, the resulting shallow junction allowed to improve the internal quantum efficiency at short wavelengths, which is particularly adapted to space applications

Estilos ABNT, Harvard, Vancouver, APA, etc.

30

Hayes, Maxim. "Intégration de collecteurs de charges avancés dans les cellules solaires bifaciales à haut rendement : vers un procédé générique pour les nouveaux matériaux silicium". Electronic Thesis or Diss., Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0519.

Texto completo da fonte

Resumo:

L'industrie PV connaît un fort engouement pour les cellules PERC. Néanmoins leurs performances sont limitées par deux sources de recombinaison des porteurs de charge: au niveau de l'émetteur obtenu par diffusion de P, et en face arrière aux interfaces Al-Si. L'objectif principal de cette thèse vise à limiter ces pertes en intégrant deux nouveaux collecteurs. Le premier est un émetteur sélectif (ES) obtenu par implantation ionique à immersion plasma (PIII) de P. Le second concerne un contact passivé (CP) constitué d'un film de silicium polycristallin (poly-Si) dopé au B sur un oxyde mince. Dans un second temps, les travaux s'intéressent à la compatibilité entre ces collecteurs et les plaquettes de Si issues de lingots fabriqués par solidification dirigée. Un procédé de masquage in situ des implantations PIII a permis d'élaborer des ES avec une bonne maîtrise de la géométrie du motif et des niveaux de dopage. Ensuite, un éventail de techniques pour la métallisation du poly-Si(B) a été étudié. La voie de métallisation par sérigraphie de pâtes traversantes est la plus encourageante à l'heure actuelle. Elle permet l'utilisation de couches hydrogénantes non sacrificielles qui ont mené à l'obtention de précurseurs de cellules avec un excellent niveau de passivation. Néanmoins, la résistance de contact entre le métal et le poly-Si(B) demeure à ce jour trop élevée pour une intégration optimale. Enfin, l'association de Si multicristallin avec différents CP a montré la propension de ces derniers à générer un effet getter externe efficace. Cela laisse envisager une très bonne compatibilité entre l'architecture cellule développée et les Si bas-coût et à faible emprunte carbone
Thanks to a relatively simple fabrication process and high conversion efficiency values the PERC structure is well established at the industrial level. Nevertheless, industrial PERC solar cells performances are mostly limited by two charge carrier recombination sources: P thermally diffused emitter on the front side and the Al-Si interfaces at the rear contacts. The main goal of this work aims at limiting both recombination sources. A selective emitter (SE) obtained by plasma immersion ion implantation (PIII) is developed for an integration on the front side; whereas a B-doped polysilicon (poly-Si) on oxide passivated contact (PC) is integrated on the back side. The second goal of this work consists in evaluating the compatibility between these advanced carrier collectors and directionally solidified Si materials. SE featuring good geometrical properties and a well-controlled doping were fabricated thanks to an in situ localized doping process obtained with a specific mask developed for PIII. Besides, several metal deposition technologies were investigated for the poly-Si(B). Fire-through screen-printing appears as the most promising approach so far. Indeed, the deposition of a non-sacrificial hydrogen-rich layer allowed to reach an excellent surface passivation level for solar cell precursors. However, the specific contact resistivity obtained remains too high for an optimal cell integration. Lastly, the fabrication of poly-Si PC showed excellent external gettering efficiencies for multicrystalline Si. Thus, the potential of the developed cell structure to be integrated with low-cost and low carbon footprint materials is encouraging

Estilos ABNT, Harvard, Vancouver, APA, etc.

31

Veau, Antoine. "Intégration de jonctions ultra minces avec passivation tunnel : application aux générations avancées de cellules PV silicium homojonction". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALT004.

Texto completo da fonte

Resumo:

L’objectif principal de ces travaux de thèse est d’étudier des voies d’améliorations pour la fabrication du dopage n+ utilisé comme zone d’émetteur dans les cellules PV industrielles en silicium cristallin (c-Si). La technique d’implantation ionique par immersion plasma (PIII) permet un contrôle précis des profils de dopage des zones implantées. L'influence de la dose d'implantation et de la température de recuit d'activation des dopants sur les profils de dopage fabriqués sur des substrat c-Si de type p ont d'abord été étudiées. Ces dopages ont été intégrés en tant qu'émetteur dans des cellules Al-BSF (Aluminium Back Surface Field) et PERC (Passivated Emitter and Rear cells). Une analyse détaillée des pertes par recombinaisons des porteurs de charges ainsi que des pertes résistives a été menée. Pour un profil de dopage optimisé, les meilleures valeurs de densités de courant de saturation de l'émetteur ont été de 70 fA/cm². Après optimisation des cellules, des rendements de conversion records de 19,7% et 21% ont été obtenus avec des cellules Al-BSF et PERC, respectivement. La technique PIII est particulièrement adaptée à la réalisation de jonctions ultra-minces, comparé à l'implantation par faisceaux d'ions. Ainsi, différents dopages ont été testés par variation de la dose PIII et de la température de recuit sur des empilements constitué de couches de polysilicium (poly-Si) déposée par PECVD sur des substrats c-Si de type p, dont la surface a été préalablement passivée par un oxyde tunnel. D'excellentes propriétés de passivation à l'état de l'art (i-Voc ~ 730mV et J0 ~ 5fA/cm²) ont été obtenues après passivation de la surface de la couche de poly-Si par des couches de SiNx hydrogénées et un recuit de firing. Avec un profil de dopage optimisé, l'étude des pertes par recombinaisons sur des cellules Al-BSF intégrant la couche de polyslicium dopée par PIII en tant qu'émetteur a révélé une amélioration des valeurs de densités de courant de saturation de l'émetteur (54 fA/cm²)
The main objective of this thesis work is to study ways of improvement for the fabrication of n+ doping used as emitter zone in industrial PV cells made of crystalline silicon (c-Si). The plasma immersion ion implantation (PIII) technique allows precise control of the doping profiles of the implanted areas. The influence of the implantation dose and the activation annealing temperature of dopants on the doping profiles produced on p-type c-Si substrates were first studied. These dopings were integrated as emitters in Al-BSF (Aluminum Back Surface Field) and PERC (Passivated Emitter and Rear cells) cells. A detailed analysis of the losses by recombination of the charge carriers as well as the resistive losses was carried out. For an optimized doping profile, the best values of emitter saturation current densities were 70 fA / cm². After cells optimization, record conversion efficiencies of 19.7% and 21% were obtained with Al-BSF and PERC cells, respectively. The PIII technique is particularly suitable for making ultra-thin junctions, compared to implantation by ion beams. Thus, different dopings were tested by variation of the PIII dose and of the annealing temperature on stacks consisting of layers of polysilicon (poly-Si) deposited by PECVD on p-type c-Si substrates, whith surfaces previously passivated by a tunnel oxide. Excellent state-of-the-art passivation properties (i-Voc~730mV and J0 ~ 5fA/cm²) were obtained after passivation of the surface of poly-Si layers by hydrogenated SiNx layers and firing annealing. With an optimized doping profile, the study of losses by recombination on Al-BSF cells integrating the polyslicon layer doped with PIII as an emitter revealed an improvement in the values of saturation current densities of the emitter (54 fA/cm²)

Estilos ABNT, Harvard, Vancouver, APA, etc.

32

Walia, Rashi. "Solid-Hydrogel Hybrid Structural Materials for Biomedical Devices and Applications". Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29549.

Texto completo da fonte

Resumo:

Hybrid combinations of hydrogels and solid materials allow a high level of functionality for devices such as tissue engineering scaffolds and soft machines. This thesis reports a versatile strategy to develop mechanically robust solid-hydrogel hybrid materials using surface embedded radicals generated through plasma immersion ion implantation (PIII) of polymeric surfaces. Acrylamide and silk hydrogels were formed on PIII activated polytetrafluoroethylene (PTFE), polyethylene (PE) and polystyrene (PS) surfaces without any external crosslinking agents or initiators. X-ray photoelectron spectroscopy (XPS) and attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectrometry confirmed the formation of the acrylamide hydrogels. The amount of hydrogel formed on the substrate increased with incubation time, monomer concentration and temperature. Stability tests indicated that 95% of the hydrogel coating was retained even after 4-months of incubation in PBS solution. Adhesive T-peel tests results demonstrating adhesion strength of the hydrogel on the PIII-treated PTFE (PIII PTFE) interface of over 300-340 N/m. Hydrogels synthesised with fibronectin enabled cell adhesion and spreading. Thesis results show that polymers functionalized with surface-embedded radicals provide excellent solid platforms for the generation of robust and functional solid-hydrogel hybrid structures for biomedical applications.

Estilos ABNT, Harvard, Vancouver, APA, etc.

33

Assmann, Andre. "AÇO DUPLEX LDX 2101 SUBMETIDO À NITRETAÇÃO POR IMPLANTAÇÃO IÔNICA, IMPLANTAÇÃO IÔNICA POR IMERSÃO EM PLASMA E DESCARGA LUMINOSA: PROPRIEDADES MECÂNICAS E TRIBOLÓGICAS". UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2011. http://tede2.uepg.br/jspui/handle/prefix/890.

Texto completo da fonte

Resumo:

Made available in DSpace on 2017-07-21T19:26:00Z (GMT). No. of bitstreams: 1 Andre Assmann.pdf: 3125745 bytes, checksum: 38854736eae2fcc4e8c2c21a2668f387 (MD5) Previous issue date: 2011-04-27
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In the present work showing the results on mechanical and tribological properties of duplex stainless steel LDX2101 nitriding by Ion Implantation (II), Plasma Immersion Ion Implantation (PI3) and Glow Discharge (GD). Nitrogen ion implantation was performed at room temperature and 350 C. The nitrogen fluencies were combined to obtain an atomic nitrogen concentration of 27 %. The PI3 was carried out with temperatures of 300 and 350 C working in N2 atmosphere during 3 hours. For GD, the working conditions were gas mixture N2/H2 (in the ratio 80%/20%, 60%/40% and 20%/80%) and N2/CH4 (in the ratio 98%/02%) during 3 hours at temperatures of 300, 350 and 380 C. Structural characterizations of the modified layers were performed by X-Ray Diffraction (XRD) with Bragg-Brentano geometry. Hardness was obtained by instrumented indentation using Oliver and Pharr method’s with Berkovich indenter. Tribological tests were evaluated by reciprocating sliding with a WC(Co) sphere (counter body). XRD patterns for II samples showing only the formation of γN, however, samples treated by GD and PI3 showed the formation of γ’Fe4N and Fe2+XN, over there γN, as a function of the working temperature and nitriding atmosphere. After the nitriding hardness values between 8 and 20 GPa in comparison to 3 GPa of the bulk was obtained. The hardness profile of samples treated by GD at 350 and 380 C exhibit plateaulike for values of hardness between 13 and 20 GPa, indicate the formation of a thicker nitrited layer. The friction coefficient for II samples showed a strong adhesive wear. PI3 samples exhibit long running-in regimes compared to II and untreated samples. GD samples showing a predominant abrasive wear because ploughing of surface for asperities and wear particles formed between the surface and counter body. The significant decrease in the wear was observed in all GD samples, with a reduction of one order of magnitude compared to untreated sample.
No presente trabalho, são apresentados os resultados sobre as propriedades mecânicas e tribológicas do aço inoxidável duplex LDX 2101 nitretado por Implantação Iônica (II), Implantação Iônica por Imersão em Plasma (3IP) e Descarga Luminosa (DL). A Implantação Iônica de nitrogênio foi realizada em temperatura ambiente e em 350 C. As fluências utilizadas foram combinadas para obter uma concentração de átomos de nitrogênio de 27 %. A nitretação 3IP, foi realizada nas temperaturas de 300 e 350 C em atmosfera de N2 durante 3 horas. Para o tratamento por DL as condições de tratamento foram em diferentes atmosferas de N2/H2 (nas proporções de 80%/20%, 60%/40% e 20%/80%) e N2/CH4 (na proporção de 98%/02%) durante 3 horas nas temperaturas de 300, 350 e 380 C. A caracterização estrutural das camadas modificadas foi obtida através de Difração de Raios-X (DRX) com geometria Bragg-Brentano. Os perfis de dureza foram obtidos por indentação instrumentada usando o método de Oliver e Pharr com indentador do tipo Berkovich. Testes tribológicos foram realizados com tribômetro do tipo pino sobre disco em movimento recíproco com uma esfera de WC(Co) de contra corpo. Os padrões de DRX para amostras tratadas por II apresentaram apenas a formação de γN, contudo, as amostras tratadas por DL e 3IP apresentaram a formação de γ’-Fe4N e Fe2+XN, além de γN, como função da temperatura de tratamento e da atmosfera de nitretação. Após as nitretações durezas entre 8 e 20 GPa em comparação a 3 GPa para o substrato foram obtidas. Perfis de dureza para amostras tratadas por DL em 350 e 380 C exibiram valores entre 13 e 20 GPa em forma de platô, indicando a formação de uma espessa camada nitretada. O coeficiente de atrito para as amostras tratadas por II apresentaram um forte desgaste adesivo. Amostras tratadas por 3IP exibiram longos regimes de acomodação comparados as amostras tratadas por II e a amostra referência. Amostras tratadas por DL apresentaram um predominante desgaste abrasivo devido à deformação plástica da superfície causada pelas asperidades e pelas partículas de desgaste formadas entre a superfície e o contra corpo. Uma significante diminuição no desgaste foi observada em todas as amostras tratadas por DL, com uma redução de uma ordem de grandeza quando comparado a amostra sem tratamento.

Estilos ABNT, Harvard, Vancouver, APA, etc.

34

Oliveira, Willian Rafael de. "INFLUÊNCIA DOS PARÂMETROS DE IMPLANTAÇÃO IÔNICA POR IMERSÃO EM PLASMA NA EFICIÊNCIA DA NITRETAÇÃO DO AÇO INOXIDÁVEL SUPER DUPLEX". UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2016. http://tede2.uepg.br/jspui/handle/prefix/858.

Texto completo da fonte

Resumo:

Made available in DSpace on 2017-07-21T19:25:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-03-10
This work aimed at study the correlation of variables in a plasma immersion ion implantation (PIII) system, as well as their synergistic combination for the nitriding of the UNS S32750 super duplex stainless steel ( SD 2507). The research comprised two phases, as follows. (i) Study of the system. The interconnection of variables, namely voltage (V), pulse width (L), frequency (f) and current (I), were systematically analyzed with respect to the cathode heating. A mathematical formulation was proposed for the ion average energy and the substrate temperature, which took into consideration the energy conservation in the system, and the basic theories for plasma and sheaths and the ion interaction with matter. Hereafter, such model is thought to be experimentally demonstrated, allowing inferring the actual PIII fraction of energy that is converted to heat. (ii) N-PIII of the SD. Mirror-like samples were nitrided under different V, f and L combinations, leading to the temperatures 295, 325, 355 and 400 oC. The surface characterization methods were the optical, field emission electron, and atomic force microscopies, X-ray diffraction, energy dispersive X-ray spectroscopy, backscattered electron diffraction, and instrumented indentation. The austenite and ferrite fraction in the as received material amounted to 43,7 % and 56,3 %, respectively. After nitriding, the modified layers were 0,5-1,5 m thick. Up to 355 ºC, the expanded phase N was produced in originally austenite grains, whereas Fe2-3N e Fe4N precipitates were formed in ferrite grains. The hardness profiles were similar among different temperatures and between the two phases in the same sample. However, in ferritic regions, the mechanism for plastic deformation changed from ductile to brittle. In the 400 ºC treatments, only N was formed. Finally, a correlation for the production of the expanded phase in PIII and the mean pulse energy Ei was attained, given by and . Where IN and I are the integrated intensities of diffraction peaks for austenite and expanded austenite, respectively.
O objetivo deste trabalho foi estudar o comportamento de um sistema de implantação iônica por imersão em plasma (PIII: “plasma immersion ion implantation”), em função de suas variáveis, bem como a influência destas na nitretação de superfícies do aço super duplex UNS S32750 (ou SD 2507). O trabalho foi dividido em dois momentos, como segue. (i) Estudo do sistema. O comportamento das variáveis associadas à implantação iônica, especificamente tensão (V), largura de pulsos (L), frequência (f) e corrente (I), foi sistematicamente analisado com relação ao aquecimento do cátodo. Com base na conservação de energia, física de plasmas e bainhas catódicas e interação de íons com a matéria, propôs-se uma formulação matemática relacionado a energia média dos íons à temperatura do substrato, a qual poderá, futuramente, ser posta à prova experimental, mensurando-se a fração de energia que é, de fato, transformada em calor. (ii) Nitretação por PIII do SD. Amostras com superfície especular foram nitretadas sob diferentes combinações de V, f e L, em temperaturas de 295, 325, 355 e 400 oC. As superfícies foram caracterizadas por métodos de microscopia (ótica, eletrônica com efeito de campo, de força atômica), difração de raios X, espectroscopia de raios X por energia dispersiva, difração de elétrons retroespalhados, e indentação instrumentada. O SD apresenta estrutura cristalina de austenita e ferrita na proporção de 43,7/56,3. A nitretação produziu camadas modificadas com espessura de 0,5 a 1,5 m. Observou-se, nos tratamentos até 355 ºC, a formação da fase expandida N nos grãos que originalmente eram austenita, e de precipitados de nitretos -Fe2-3N e -Fe4N em grãos de ferrita. Embora não houve diferenças significativas nos perfis de dureza, tanto entre as temperaturas quanto entre as fases em uma mesma amostra, o mecanismo de deformação plástica nas regiões ferríticas transitou de dúctil para frágil. Nas nitretações em 400 ºC, houve apenas a formação de N. Finalmente, determinou-se que a obtenção da fase expandida por PIII no SD se relaciona com a energia média por pulso Ei por e . Onde I e I são as intensidades integradas dos picos de difração da austenita expandida e da austenita, respectivamente.

Estilos ABNT, Harvard, Vancouver, APA, etc.

35

Venhaus, Thomas Joseph. "Plasma source ion implantation of high voltage electrodes". W&M ScholarWorks, 2000. https://scholarworks.wm.edu/etd/1539623981.

Texto completo da fonte

Resumo:

Field emission and breakdown characteristics of high voltage, large area electrodes determine the performance of many vacuum-based electron sources. A corroborative project with the Thomas Jefferson National Accelerator Facility involves studying the behavior of such electrodes after nitrogen ion implantation. A Plasma Source Ion Implantation (PSII) facility is designed and constructed at William and Mary, and used to treat stainless steel electrodes. PSII is a novel implantation technique developed at the University of Wisconsin-Madison. A workpiece is submerged in a quiescent plasma of the species to be implanted. A series of high, negative voltages (30--100 kV) is applied to the workpiece to accelerate the ions in the plasma, implanting them to depths of several hundred Angstroms. to characterize the response of the modified electrodes to high field gradients, fields as high as 20 MV/m are applied between parallel electrodes in a VG ESCALab MKII surface analysis system. XPS, AES, and SEM are used to characterize the surface of the cathodes. The pre-breakdown current from implanted electrodes is compared to that of thin film coated, polished, electron beam treated, and untreated electrodes. Current models to explain anomalous field emission are reviewed and considered as explanation of observed effects.

Estilos ABNT, Harvard, Vancouver, APA, etc.

36

Fu, King Yu. "Plasma implantation and deposition for advanced materials surface modification /". access full-text access abstract and table of contents, 2005. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-ap-b19887310a.pdf.

Texto completo da fonte

Resumo:

Thesis (Ph. D.)--City University of Hong Kong, 2005.
"Submitted to Department of Physics and Materials Sciences in partial fulfillment of the requirements for the degree of Philosophy of Doctor." Includes bibliographical references.

Estilos ABNT, Harvard, Vancouver, APA, etc.

37

Nassar, Rafat Mohammad. "A new tritium monitor design based on plasma source ion implantation technique". Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/13373.

Texto completo da fonte

Resumo:

Tritium is an important isotope of hydrogen. The availability of tritium in our environment is manifest through both natural and artificial sources. Consequently, the requirement for tritium handling and usage will continue to increase in the future. An important future contributor is nuclear fusion power plants and facilities. Essential safety regulations and procedures require effective monitoring and measurements of tritium concentrations in workplaces. The unique characteristics of tritium impose an important role on the criteria for its detection and measurement. As tritium decays by the emission of soft beta particles, maximum 18 keV, it cannot be readily detected by commonly used detectors. Specially built monitors are required. Additional complications occur due to the presence of other radioactive isotopes or ambient radiation fields and because of the high diffusivity of tritium. When it is in oxidized form it is 25000 times more hazardous biologically than when in elemental form. Therefore, contamination of the monitor is expected and compound specific monitors are important. A summary is given of the various well known methods of detecting tritium-in-air. This covers the direct as well as the indirect measuring techniques, although each has been continually improved and further developed, nevertheless, each has its own limitations. Ionization chambers cannot discriminate against airborne P emitters. Proportional counters have a narrow operating range, 3-4 decades, and have poor performance in relatively high humid environments and require a dry counting gas. Liquid scintillation counters are sensitive, but inspection of the sample is slow and they produce chemical liquid waste. A new way to improve the sensitivity of detecting tritium with plastic scintillators has been developed. The technique is based on a non-line-of-sight implantation of tritium ions into a 20 mum plastic scintillator using a plasma source ion implantation (PSII) technique, This type of source is different, superior to the line-of-sight implantation and requires no additional beam handling. It is capable of implanting ion species in a broad beam configuration into the entire surface of a target. The technique requires a special ion source with special characteristics of the type obtained from a surfatron plasma source. This ion source has a large high ion density plasma with minimum contamination and produces ions of low temperature. It was constructed to ionize the sampled air and to produce a plasma over a wide range of pressure, 4-0.1 mTorr. A plasma source ion implantation cell was designed and constructed using mathematical modeling with personal computer, to optimize the essential variables of the design and to estimate the implantation rate under different operation conditions. Also, a high voltage pulse modulator was designed and constructed to produce a series of 10 musec pulses (up to 2 MHz) with a maximum magnitude of -60 kV. The developed device was capable of ionizing air samples and implanting the resulting ions into a plastic scintillator. Two different methods to enhance the collection and deposition of the tritium ions, have been proposed and assessed. A movable prototype device for monitoring environmental tritium in air has been designed and constructed. Although this prototype was not fully tested, the primary calculations have shown that measurable concentrations of tritium ions can be collected from an air sample, with tritium activity ranging from 0.3 Bq/cm3 down to 0.03 mBq/cm3, in a short time, to the order of seconds, on-line. This sensitivity fulfills the requirement for environmental monitoring.

Estilos ABNT, Harvard, Vancouver, APA, etc.

38

Arab, Zeinab. "Plasma based ion implantation and plasma hydrogenation of silicon for photovoltaics : influence on the electrical properties". Poitiers, 2009. http://www.theses.fr/2009POIT2263.

Texto completo da fonte

Resumo:

This report reviews the history, the present status and possible future developments of photovoltaic industry. The base material in this domain is crystalline silicon. Although c-Si is not the optimal material from a solid state physics point of view it dominates the market and will continue to do this. A considerable part of this study deals with quality improvement of crystalline silicon via passivation by hydrogenation and hydrogen implantation (PBII). Some conventional in-line implantation has also been performed in order to compare these two implantation methods. Mono crystalline p-type (CZ) silicon (100) wafers with a thickness of ~ 700 µm and estimated resistivity of 5-10 Ωcm with boron concentration of about 1015 cm-3 are used as sample for ion implantation. For hydrogenation experiences multi crystalline p-type silicon wafers fabricated by Photowat with a thickness of ~300µm and estimated resistivity of 1-2 Ωcm with boron concentration of about 1016 cm-3 have been used. The implantation is realized at working pressure regulated at 2 Pa with a hydrogen gas flew of 20 Sccm. Then the plasma is generated with a forward power of 700W, high voltage pulses of 20 kV with length of 10 µs and a frequency of 200 Hz. Different hydrogen dose of 1015 to 2×1017 at. H/cm2 are applied into the samples. Hydrogenation on its turn is realized with the same condition of plasma generation at different temperatures (300°-800°C) and pressures (2-12 Pa). TEM micrographs show the formation of different kind of defects. For low hydrogen dose from 1015 to 1016 at. H/cm2 the modifications consist mainly of planar defects as (100) platelets, some dislocation loops and interstitials. Higher dose (1016 to 1017 at. H/cm2) results in the formation of (100) and (111) platelets and more dislocations and micro-cracks giving rise to the formation of blistering and exfoliation. However TEM doesn’t show any significant micro-structural modifications after hydrogenation. NRA study has been done in order to determine the hydrogen profile for both implanted and hydrogenated silicon. Hydrogen concentration increase with implantation dose increasing and can reach up to 25 atomic % for hydrogen dose of 2×1017 at. H/cm2. Meanwhile hydrogenation at relatively high temperature results in low hydrogen concentration. The maximum hydrogen concentration is enriched at 400°C-2 hours hydrogenation. Sinton lifetime measurement has also been used in order to determine the carrier lifetime in hydrogenated microcrystalline silicon. Passivation is found to be more effective for hydrogenation realized at low temperature (below 600°C) because at higher temperature the out-diffusion is more pronounced and will influence the effect of hydrogenation
Ce rapport présente l'histoire et le statut du développement de l'industrie photovoltaïque aujourd'hui et dans l'avenir. Le matériel de base dans ce domaine est le silicium cristallin. Bien que c-Si ne soit pas le meilleur choix du point de vue de la physique d'état solide il domine encore le marché. Une partie importante de cette étude est consacrée à l'amélioration de la qualité du c-Si via la passivation par hydrogénation et l'implantation ionique par immersion plasma (PIII). Des expériences ont été effectuées afin de comparer le PIII avec la méthode conventionnelle d'implantation (implantation en ligne). Pour les expériences de PIII, les substrats utilisés étaient du silicium mono cristallin de type p d'orientation (100) avec une épaisseur d'environ 700 µm, une résistivité estimée entre 5 et 10 Ωcm et une concentration de dopant de 1015 cm-3, alors que pour les expériences d'hydrogénation nous avons utilisé des plaquettes de silicium multi cristallin de type p fabriquées par Photowat d'une épaisseur d’environ 300 µm, une résistivité de 1 à 2 Ωcm et une concentration de dopant de 1016 cm-3. L'implantation a été réalisée sous une pression de 2 Pa avec le débit d'hydrogène réglé à 20 sccm. Ensuite, le plasma a été crée à l'aide d'une puissance incidente de 700 W avec des impulsions de 20 kV d'une durée de 10 µs et une fréquence de 200 Hz. Différentes doses de 1015 à 2×1017 at. H/cm2 d'hydrogène ont été appliquées aux échantillons. Dans le cas de l'hydrogénation, la création du plasma est identique à celle du PIII mais avec différentes température (300°C-800°C) et pressions (2-12 Pa). Les résultats de la microscopie électronique en transmission révèlent la formation de différents types de défauts. Pour les doses assez base de 1015 à 1016 at. H/cm2 les modifications sont principalement des « platelets », des boucles de dislocations et des défauts interstitiels. Les doses plus élevées (1016 à 1017 at. H/cm2) permettent la formation des « platelets » d'orientation (100) ainsi que (111) et augmentent le nombre de dislocations et de microcavités qui favorisent la formation des claques (blistering et exfoliation). Cependant, les résultats de TEM ne montrent pas les importantes modifications microstructurales après hydrogénation. Les mesures de NRA ont été réalisées pour déterminer le profil d'hydrogène dans les échantillons implantés ainsi que dans les échantillons hydrogénés. La concentration d'hydrogène augmente avec l'augmentation de la dose d'implantation et peut acquérir jusqu'au 25 at. % (dose = 2×1017 at. H/cm2). Les mesures de NRA montrent que pour les échantillons hydrogénés à des températures relativement élevés la concentration d'hydrogène est faible. La concentration maximale d'hydrogène a été obtenue à partir d'un échantillon hydrogéné à 400°C-2 heures. La méthode de mesure de la durée de vie de Sinton a été utilisée lors de cette étude pour déterminer la durée de vie des porteurs dans le silicium multi cristallin. La passivation via hydrogénation est encore plus efficace à de basses températures (inférieur à 600°C) car sous les températures élevées l'exo-diffusion d'hydrogène sera plus prononcée et va influencer l'effet d'hydrogénation

Estilos ABNT, Harvard, Vancouver, APA, etc.

39

Batocki, Regiane Godoy de Santana [UNESP]. "Implantação iônica por imersão em plasma - IIIP - de argônio, nitrogênio e hélio em hexametildissilazano polimerizado a plasma". Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/103743.

Texto completo da fonte

Resumo:

Made available in DSpace on 2014-06-11T19:32:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-27Bitstream added on 2014-06-13T20:04:23Z : No. of bitstreams: 1 batocki_rgs_dr_guara.pdf: 753160 bytes, checksum: 45bdf421ee548b969fb254971bfe730c (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Filmes finos polimerizados a plasma apresentam várias aplicações nas indústrias óticas, elétrica, mecânica de alimentos, de biomateriais entre outras, devido suas interessantes propriedades químicas e físicas. No entanto, as aplicações para os filmes finos podem ser limitadas em função de algumas de suas características mecânicas e de superfície. Neste trabalho, filmes finos poliméricos foram depositados por radiofrequência a partir de plasmas de hexametildissilazano mantido a baixa pressão. Posteriormente, foram implantados íons de argônio, hélio e nitrogênio nestes filmes através da implantação iônica por imersão a plasma (IIIP). Após os tratamentos, os filmes finos provenientes da polimerização a plasma do hexametildissilazano apresentaram modificações em suas estruturas moleculares e composição química através das análises infravermelha e XPS. O XPS revelou um aumento nas concentrações de oxigênio e decréscimo de carbono e nitrogênio. Este fato indica aumento no nível e entrelaçamento, ramificação e reticulação das cadeias poliméricas para todos os íons implantados. Verificou-se também que a IIIP promoveu mudanças na molhabilidade com variações nos ângulos de contato de 100° para 10°; alterações nos índices de refração entre 1,65 a 2,10; modificações na dureza e módulo elástico de 0,8 a 3,3 GPa e 6,0 a 52,0 GPa respectivamente, assim como redução na taxa etching de 34,0 para 20,0 Å/min.
Plasma polymerized thin films have many applications in optical, electrical, mechanical, food, biomaterial industries among others, due to their interesting chemical and physical properties. Polymer thin films applications, however, can be limited because of some mechanical and surface characteristics. In this work, thin polymer films were deposited from radiofrequency plasmas of hexamethyldisilazane at low pressure. Then, these films were implanted with argon, helium and nitrogen ion, by plasma immersion ion implantation (PIII). After the treatments, plasma polymerized hexamethyldisilazane thin films presented modifications in their molecular structure and chemical composition by infrared and XPS analysis. XPS revealed an increase in the oxygen, decrease in nitrogen and carbon concentrations. This fact indicates increased crosslinking of the polymeric chains of all implanted ions. It was also verified that a PIII caused modification in wettability, changing the contacts angles from 100° to 10°. Modifications were also observed in the refractive index from 1,65 to 2,10; in hardness and in the elastic modulus from 0,8 a 3,3 GPa and 6,0 to 52,0 GPa respectively. The study showed a decrease in etching rate from 34,0 to 20,0 Å/min.

Estilos ABNT, Harvard, Vancouver, APA, etc.

40

Batocki, Regiane Godoy de Santana. "Implantação iônica por imersão em plasma - IIIP - de argônio, nitrogênio e hélio em hexametildissilazano polimerizado a plasma /". Guaratinguetá : [s.n.], 2009. http://hdl.handle.net/11449/103743.

Texto completo da fonte

Resumo:

Resumo: Filmes finos polimerizados a plasma apresentam várias aplicações nas indústrias óticas, elétrica, mecânica de alimentos, de biomateriais entre outras, devido suas interessantes propriedades químicas e físicas. No entanto, as aplicações para os filmes finos podem ser limitadas em função de algumas de suas características mecânicas e de superfície. Neste trabalho, filmes finos poliméricos foram depositados por radiofrequência a partir de plasmas de hexametildissilazano mantido a baixa pressão. Posteriormente, foram implantados íons de argônio, hélio e nitrogênio nestes filmes através da implantação iônica por imersão a plasma (IIIP). Após os tratamentos, os filmes finos provenientes da polimerização a plasma do hexametildissilazano apresentaram modificações em suas estruturas moleculares e composição química através das análises infravermelha e XPS. O XPS revelou um aumento nas concentrações de oxigênio e decréscimo de carbono e nitrogênio. Este fato indica aumento no nível e entrelaçamento, ramificação e reticulação das cadeias poliméricas para todos os íons implantados. Verificou-se também que a IIIP promoveu mudanças na molhabilidade com variações nos ângulos de contato de 100° para 10°; alterações nos índices de refração entre 1,65 a 2,10; modificações na dureza e módulo elástico de 0,8 a 3,3 GPa e 6,0 a 52,0 GPa respectivamente, assim como redução na taxa etching de 34,0 para 20,0 Å/min.
Abstract: Plasma polymerized thin films have many applications in optical, electrical, mechanical, food, biomaterial industries among others, due to their interesting chemical and physical properties. Polymer thin films applications, however, can be limited because of some mechanical and surface characteristics. In this work, thin polymer films were deposited from radiofrequency plasmas of hexamethyldisilazane at low pressure. Then, these films were implanted with argon, helium and nitrogen ion, by plasma immersion ion implantation (PIII). After the treatments, plasma polymerized hexamethyldisilazane thin films presented modifications in their molecular structure and chemical composition by infrared and XPS analysis. XPS revealed an increase in the oxygen, decrease in nitrogen and carbon concentrations. This fact indicates increased crosslinking of the polymeric chains of all implanted ions. It was also verified that a PIII caused modification in wettability, changing the contacts angles from 100° to 10°. Modifications were also observed in the refractive index from 1,65 to 2,10; in hardness and in the elastic modulus from 0,8 a 3,3 GPa and 6,0 to 52,0 GPa respectively. The study showed a decrease in etching rate from 34,0 to 20,0 Å/min.
Orientador: Rogério Pinto Mota
Coorientador: Deborah Cristina Ribeiro Santos
Banca: Roberto Yzumi Honda
Banca: Elson de Campos
Banca: Emerson Ferreira de Lucena
Banca: José Roberto Ribeiro Bortoletto
Doutor

Estilos ABNT, Harvard, Vancouver, APA, etc.

41

Tuckute, S., e L. L. Pranevicius. "Separation of Hydrogen from Water Molecules by Ion Implantation into Thin Ti Films". Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35410.

Texto completo da fonte

Resumo:

The potential of hydrogen as primary gas source has generated considerable interest in hydrogen separation technologies. In the present work, the method of ion implantation has been used to separate hydrogen from energetic water molecules penetrating into Ti films. According to the results of the present study, the technique and method of implantation are capable of splitting water molecular ions into their constituent atoms with accommodation of oxygen and hydrogen atoms in interstitials of Ti film. The experimental distribution profiles are fitted with the simulated results based on the analysis of solutions of rate equations including processes of molecular ion implantation and diffusion. The dominant mechanisms transporting incident particles from the surface into the bulk are discussed. The obtained results are compared to literature data on the widely studied titanium–hydrogen bulk system. The experimental and simulation results are in consistency that molecular ions upon entering the substrate break up into constituent atoms and separation of hydrogen occurs. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35410

Estilos ABNT, Harvard, Vancouver, APA, etc.

42

Meyer, Kevin Alan. "Development of a plasma source ion implantation facility for the modification of materials' surfaces". Doctoral thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/6538.

Texto completo da fonte

Resumo:

Bibliography: p. 197-203.
In Plasma Source Ion Implantation high energy [10-50 keV] plasma ions are implanted into materials to modify surface properties, achieving surface hardening, increased wear and corrosion resistance. Plasma Source Ion Implantation is alos used for doping semiconductors and could form an essential step in the manufacture of multilayered wafers. This thesis describes the development and construction of the plasma implantation facility at the Materials Research Group of the Naitonal Accelerator Centre; in particular, the development of the Plasma Assisted Materials Modification Laboratory, the analytical tools available at the Materials Research Group and surrounding universities, basic research into the implantation of steels, the x-rays emitted as a side-effect of plasma source ion implantation and the development of an analytical technique of interest to silicon wafer-cutting technologies.

Estilos ABNT, Harvard, Vancouver, APA, etc.

43

LE, COEUR FREDERIC. "Décharges excitées à la résonance cyclotronique électronique distribuée et générateurs à transformateur d'imulsions pour implantation ionique par immersion plasma". Grenoble INPG, 1999. http://www.theses.fr/1999INPG0127.

Texto completo da fonte

Resumo:

La technique d'implantation ionique par immersion plasma (piii) consiste a appliquer a un substrat conducteur plonge dans le plasma des impulsions negatives haute tension. Les ions positifs presents dans le plasma sont alors acceleres vers la surface du substrat ou ils sont implantes. Les principaux avantages de la technique piii par rapport a l'implantation par faisceau d'ions sont de pouvoir traiter facilement des formes complexes ou des grandes surfaces, et de preparer les surfaces sous bombardement ionique de faible energie avant l'etape d'implantation. Par contre, la selection des ions en masse n'est pas possible. En raison de l'expansion de la gaine ionique (quelques dizaines de cm), des volumes importants de plasma a bas pression autour du substrat sont necessaires. Pour cette raison, les decharges multipolaires, qui permettent une ionisation peripherique face au substrat et autorisent l'extension d'echelle des plasmas a basse pression, sont bien adaptees au procede piii. Cependant, l'utilisation des filaments pour produire des plasmas reactifs dans les structures multipolaires doit etre supprimee au profit des sources plasmas decr (resonance cyclotronique electronique distribuee). Le principe et les performances des plasmas decr sont presentes. Pour produire les impulsions haute tension - fort courant necessaires au procede piii, des generateurs utilisant des transformateurs d'impulsions, ou la tension au primoire est pilotee par des commutateurs a transition et ou l'energie est stockee a basse tension, ont ete developpes. Les performances enregistrees avec ce type de generateur d'impulsions (100 kv - 100 a) ont ete obtenues d'abord sur une resistance test, plus sur un substrat plonge dans un plasma. Finalement les potentialites et les performances du dispositifs d'implantation sont demontrees a partir de quelques exemples d'applications choisis pour leur caractere illustratif.

Estilos ABNT, Harvard, Vancouver, APA, etc.

44

Marot, Laurent. "Développement d'un nouveau système d'implantation ionique en immersion plasma et analyses des processus de nitruration". Phd thesis, Université de Poitiers, 2001. http://tel.archives-ouvertes.fr/tel-00003632.

Texto completo da fonte

Resumo:

L'objectif de ce travail était double : le développement d'un réacteur d'implantation par immersion plasma et l'analyse des mécanismes de nitruration. En ce qui concerne la nitruration des aciers, nous avons montré que des traitements de nitruration au potentiel flottant à des températures aussi basses que 300 °C étaient réalisables dans le réacteur URANOS avec des longueurs de diffusion de plusieurs centaines de microns. Pour les aciers faiblement alliés, les diffusions réalisées à 380 °C, conduisent à une amélioration notable des propriétés mécaniques de surface. Ainsi la dureté de surface est triplé et la limite d'endurance en fatigue augmente de 30 %, pour un traitement de 4 heures. Dans le cas des aciers inoxydables, des couches très dures (5 fois la dureté du substrat) d'austénite dilatée sont formées en surface. Le rôle de l'hydrogène dans le plasma, consiste non seulement à réduire la couche d'oxyde présente en surface du matériau, mais surtout à accélérer la cinétique d'enrichissement d'azote en profondeur, cela quelque soit le type d'acier. Le second objectif de cette thèse était le développement d'un nouveau réacteur d'implantation par immersion plasma. A basse température l'implantation d'azote sur des aciers entraîne la formation d'une couche dure de surface. L'implantation d'azote sur des alliages base aluminium révèle, toujours à basse température, la formation d'un film de nitrure d'aluminium (AlN). La grande originalité du réacteur que nous avons développé est de pouvoir réaliser des implantations à température élevée (300-1000 °C). Nous avons ainsi pu montrer qu'à 900 °C, sur des alliages base titane, on peut réaliser la croissance de films épais de TiN et Ti2N et au-delà induire la formation d'une couche de diffusion sur plus de 60 µm. L'implantation de silicium à température contrôlée a permis de montrer qu'un film transparent, de nitrure de silicium, pouvait croître grâce à un transport combinant l'action thermique et l'implantation ionique. Dans ce cas et pour des doses suffisamment élevées, la couche atteint 40 nanomètres et présente la stœchiométrie du nitrure Si3N4. Ce résultat est parfaitement inaccessible aux autres techniques de nitruration puisque, la croissance de nitrure est auto-limitée à des épaisseurs inférieurs à 5 nm.

Estilos ABNT, Harvard, Vancouver, APA, etc.

45

Fouquet, Valérie. "Etude des mécanismes d'implantation et diffusion lors de la nitruration du titane et de Ti-6Al-4V par implantation ionique en immersion plasma". Poitiers, 2004. http://www.theses.fr/2004POIT2271.

Texto completo da fonte

Resumo:

L'objectif de ce travail est d'étudier les mécanismes d'implantation et de diffusion lors de la nitruration du titane et de Ti-6Al-4V par implantation ionique en immersion plasma. Des études chimiques et microstructurales ont permis de préciser les caractéristiques des phases formées selon les conditions de traitements. A basse température, le processus d'implantation est le mécanisme principal de formation des nitrures tandis qu'à haute température, la part de la diffusion thermique devient prédominante. Une résolution numérique de la première loi de Fick a permit de conclure que, grâce aux défauts d'implantation, le coefficient de diffusion dans la couche de nitrure de surface est fortement augmenté. Constamment alimentée en azote par l'implantation, la couche de nitrure constitue une source pour la diffusion en profondeur alors que dans un traitement sans implantation, elle agit comme une barrière de diffusion
The aim of this work is to study the implantation and diffusion mechanisms occuring during nitridation of titanium and of Ti-6Al-4V by plasma based ion implantation. Chemical and microstructural studies allow the determination of the characteristics of the phases formed depending on the treatment parameters. The implantation is the main formation mechanism of nitrides at low temperature whereas the nitridation is mainly controlled by the thermally activated diffusion at high temperature. By means of a numerical resolution of the equation of diffusion taking into account the experimental observations, implantation-induced defects have been shown to enhance the diffusion coefficient in the nitride layer. The in-depth nitridation of titanium is however favoured by the continuously implanted nitrogen in the nitride layer which acts as an in-depth source. On the contrary, in a thermal-activated treatment, the nitride forms a diffusion barrier which limits the later incorporation of nitrogen

Estilos ABNT, Harvard, Vancouver, APA, etc.

46

Vempaire, David. "Modification des propriétés magnétiques de couches minces de nickel et de manganèse et réalisation de microstructures magnétiques par implantation ionique en immersion plasma". Université Joseph Fourier (Grenoble), 2004. http://www.theses.fr/2004GRE10252.

Texto completo da fonte

Resumo:

Nous avons tout d'abord etudie le depot de couches minces de manganese et de nickel sur silicium 100 par pulverisation ionique assistee par plasma micro-onde mul tidipolaire. Les couches de nickel et de manganese deposees ont ensuite ete implantees par de l'azote en utilisant la technique d'implantation ionique en immersion plasma assistee par plasma micro-onde decr. Cette technique nous a permis de synthetiser les nitrures ni3n et mn4n malgre la metastabilite du ni3n et la forte reactivite chimique a l'oxygene du manganese. Nous avons ensuite implante de l'azote dans une double couche ni sur mn pour les nitrurer simultanement en formant l'empilement ni3n sur mn4n. Le caractere metastable de ni3n et la forte affinite du manganese pour l'azote, traduit par une grande difference d'enthalpie de formation des composes ni3n et des nitrures de manganese, a conduit l'azote implante a diffuser entierement dans le manganese lors du recuit post implantation. Pour finir, nous avons initier l'etude de la realisation d'une microstructure magnetique par implantation d'azote dans une couche de nickel a travers un masque organique
WE FIRST OF ALL STUDIED THE DEPOSIT OF THIN LAYERS OF MANGANESE AND NICKEL ON SILICON 100 USING THE PULVERIZATION ASSISTED BY MICROWAVE MUL TIDIPOLAR PLASMA TECHNIQUE. THE LAYERS OF NICKEL AND MANGANESI DEPOSITED WERE TH EN IMPLANTED WITH NITROGEN BY USING THE PLASMA BASED IMMERSION IMPLANTATION TECHNIQUE ASSISTED BY A MICROWAVE DE CR PLASMA. THIS TECHNIQUE ENABLED TO SYNTHESIZE THE NITRIDES NI3N AND MN4N lN SPITE OF THE METASTABILITY OF NI3N AND THE STRONG CHEMICAL REACTIVITY OF MANGANESE WITH OXYGEN. THEN WE HAVE IMPLANTED NITROGEN lN A DOUBLE LAYER NI ON MN SIMUL TANEOUSL Y TO NITRIDE THEM BY MAKING NI3N STACKING ON MN4N. THE METASTABILITY OF NI3N AND THE STRONG AFFINITY OF MANGANESE FOR NITROGEN, HAVE MADE NITROGEN IMPLANTED ENTIREL Y DIFFUSING lN MANGANESE DURING THE ANNEALING. THEN, WE HAVE INITIATED THE STUDY OF THE REALIZATION OF A MAGNETIC MICROSTRUCTURE BY NITROGEN IMPLANTATION lN A LAYER OF NICKEL THROUGH AN ORGANIC MASK

Estilos ABNT, Harvard, Vancouver, APA, etc.

47

Renaud, Justine. "Application des faisceaux d'ions focalisés à la création de centres NV du diamant. Caractérisation de ces faisceaux d'ions issus d'une source plasma". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN027.

Texto completo da fonte

Resumo:

Depuis plus de 45 ans, les colonnes à faisceaux d'ions focalisés FIB à base de source à métal liquide (Ga) sont utilisées pour l'élaboration, la modification ou l'analyse de nanostructures. Beaucoup plus récemment, moins de 10 ans, les sources plasma sont intégrées dans les FIB afin de répondre aux besoins d'analyse de défaillance mais également de préparation d'échantillons. Ce marché des FIB plasma est en forte progression ces derniers années et s'accompagne d'une amélioration permanente des spécifications de cette technologie encore jeune. Il est donc nécessaire de caractériser au mieux ces sources afin de pouvoir améliorer l'optique associée. Dans cette thèse, nous présentons le développement d'une nouvelle colonne FIB fonctionnant avec une source d'ions plasma, dédiée à la création de centres NV, ainsi que le développement d'un outil permettant de caractériser les performances de cette source.Étant donné le contexte de ces travaux, la première partie du manuscrit est consacrée à la présentation de la technologie FIB, de son fonctionnement et de ses applications. Dans le second chapitre, nous présentons le développement d'une colonne FIB dédiée à l'implantation d'ions azote pour la création contrôlée de centres colorés NV dans des diamants. Nous commençons par introduire les propriétés uniques des centres NV ainsi que les méthodes usuelles pour leur création. Nous présentons ensuite les différentes étapes de la caractérisation de cette colonne FIB. Les implantations réalisées au cours de ce travail ont pu être utilisées pour le développement d'une nouvelle application des diamants dopés.Dans le dernier chapitre du manuscrit, nous nous intéressons à la conception d'un banc de test permettant d'obtenir les paramètres clés de la source d'ions, à savoir la dispersion en énergie et l'émittance. Les méthodes usuelles de mesure de ces paramètres sont présentées puis le fonctionnement du banc de test est entièrement décrit. Nous présentons ensuite les mesures effectuées avec des faisceaux d'ions xénon puis oxygène. Certains paramètres de la source d'ions plasma ont ainsi été obtenus
For more than 45 years, focused ion beams FIB columns based on liquid metal ion sources (Ga) have been used for the development, modification or analysis of nanostructures. Much more recently, less than 10 years ago, plasma sources are integrated in FIBs to meet the needs of failure analysis as well as sample preparation. This plasma FIB market has grown strongly in recent years and is accompanied by a permanent improvement of the specifications of this young technology. Therefore, it is necessary to characterize these sources in order to improve the associated optics. In this thesis, we present the development of a new FIB column working with a plasma ion source, dedicated to the creation of NV centers, as well as the development of a system dedicated to the characterization of the performances of this source.Given the context of this work, the first part of the manuscript is dedicated to the presentation of FIB technology, its operation and its applications. In the second chapter, we present the development of a FIB column dedicated to the implantation of nitrogen ions for the controlled creation of NV color centers in diamonds. We begin by introducing the unique properties of NV centers as well as the usual methods for their creation. Then we present the different steps of the characterization of this FIB column. The implantations carried out during this work have been used for the development of a new application of doped diamonds.In the last chapter of the thesis, we are interested in designing a test bench to obtain the key parameters of the ion source, namely energy dispersion and emittance. The usual methods for measuring these parameters are presented and the operation of the test bench is fully described. Then we then present the measurements made with beams of xenon ions and oxygen ions. Some parameters of the plasma ion source have thus been obtained

Estilos ABNT, Harvard, Vancouver, APA, etc.

48

Kapser, Stefan [Verfasser], Rudolf [Akademischer Betreuer] Neu, Rudolf [Gutachter] Neu e Johannes [Gutachter] Barth. "Deuterium Permeation Through Tungsten Driven by Plasma-Based Low-Energy Ion Implantation / Stefan Kapser ; Gutachter: Rudolf Neu, Johannes Barth ; Betreuer: Rudolf Neu". München : Universitätsbibliothek der TU München, 2018. http://d-nb.info/1176107046/34.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

49

Liao, Jiunn-Der. "Modifications physico-chimiques et mécaniques du polyéthylène et du polypropylène par implantation ionique, plasma micro-ondes,bombardement d'électrons et irradiation gamma". Grenoble INPG, 1995. http://www.theses.fr/1995INPG4202.

Texto completo da fonte

Resumo:

La surface d'une polyolefine traitee par plasma micro-ondes ou par faible dose d'implantation ionique d'azote devient mouillable. Pour obtenir des peroxydes polarisables sur une polyolefine, un traitement par plasma d'argon de courte duree est suffisant. Les analyses xps couplees avec les resultats obtenus en resonance paramagnetique electronique, par decomposition des peroxydes, par mesures de mouillabilite et par l'exploitation des spectres actifs en infrarouge ont montre que les structures oxydees, formees par differentes techniques de traitement, jouent un role important pour interpreter la variation des proprietes chimiques a la surface du polymere. Compare a l'implantation ionique, le traitement par plasma micro-ondes, en particulier par plasma argon, produit plus de groupes polarisables. Il est interessant pour les applications de greffage. La durete et le module d'elasticite, mesures par nanoindentation sur une polyolefine augmentent avec une dose appropriee d'implantation ionique. Une dose de 1,4 x 10#1#7 ions. Cm#-#2 permet de multiplier par 15 la durete du polyethylene a tres haut poids moleculaire et par 7 son module d'elasticite a une profondeur de 30 nm. Le passage du comportement visco-plastique a quasi-elastique est mis en evidence. L'epaisseur de la couche modifiee depasse 300 nm. L'etude du couple de frottement entre sphere metallique et cupule en polyethylene montre que l'implantation ionique du polymere permet de reduire la vitesse d'usure du polyethylene, par amelioration de ses proprietes mecaniques liees a la formation d'une couche reticulee, dure et elastique. Les effets des traitements de surface sur les polymeres utilises comme biomateriaux permettent d'adapter les proprietes en surface des applications specifiques

Estilos ABNT, Harvard, Vancouver, APA, etc.

50

Basso, Rodrigo Leonardo de Oliveira. "Efeito do carbono no processo de nitrocarburização com plasma pulsado da liga metálica AISI H13". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277746.

Texto completo da fonte

Resumo:

Orientador: Fernando Alvarez
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
Made available in DSpace on 2018-08-11T05:33:37Z (GMT). No. of bitstreams: 1 Basso_RodrigoLeonardodeOliveira_D.pdf: 34307948 bytes, checksum: fd2817ddc7e94a48942bf4136fdb0472 (MD5) Previous issue date: 2007
Resumo: Este trabalho apresenta um estudo sobre os efeitos da incorporação de carbono e nitrogênio na formação de uma camada monofásica, compacta e homogênea, composta por carbonitretos do tipo e -Fe2-3(C,N), na superfície da liga metálica AISI H13. Também são apresentados estudos sobre os efeitos da incorporação desses elementos nas propriedades mecânicas, químicas e na microestrutura da superfície da liga metálica. A incorporação desses elementos na superfície do material foi feita utilizando-se o tratamento termoquímico de nitrocarburização por plasma pulsado em atmosferas contendo N2+ H2+ CH4 em diferentes proporções. Além da composição da atmosfera de tratamento, também foram variadas a temperatura e o tempo de tratamento. De maneira a complementar o estudo do comportamento da liga metálica frente ao tratamento termoquímico a plasma, também foram preparadas amostras com atmosferas oxidantes contendo CO2. A análise da composição química da superfície das amostras foi feita através de espectroscopia de fotoelétrons e mostra que a incorporação de nitrogênio sofre grande influência da quantidade de gás contendo carbono, presente no plasma. Porém a incorporação desses elementos não é diretamente proporcional à concentração do gás contendo esse elemento. Ao contrário do esperado, aumentando-se suficientemente a concentração desses elementos na atmosfera de tratamento, não acarreta em aumento na concentração dos mesmos no material. Por outro lado a análise através de difração de raios X revelou a formação de estruturas cristalinas consistentes com o diagrama de fases do sistema Fe-C-N. Para menores concentrações de compostos de carbono no plasma, a formação de nitretos e carbonitretos é predominante enquanto que maiores quantidades desse elemento levam ao surgimento da fase cementita e -Fe3 C, indesejável por possuir baixa resistência mecânica. As propriedades mecânicas da superfície foram estudadas através de medidas de nano e micro-dureza e seus resultados indicam que, como esperado, amostras com maior quantidade de nitrogênio incorporada possuim maior dureza da superfície. Esse comportamento é condizente com a microestrutura observada por microscopia eletrônica de varredura que mostra o entrelaçamento dos grãos da estrutura do aço e o preenchimento de seus contornos com carbonitretos de ferro que dificultam a movimentação dos planos cristalinos do cristal aumentando sua dureza. Foi verificado que as concentrações de carbono e de nitrogênio contido no material exercem grande influência sobre a reatividade da superfície das amostras frente a processos corrosivos em meios contendo íons cloreto. Esse comportamento foi verificado através de medidas de corrosão em solução aquosa de NaCl a 0,9 vol.%. Novamente os resultados apontam que maior concentração de nitrogênio é responsável por conferir a superfície maior proteção contra corrosão. Esses resultados são atribuídos a presença de uma mono-fase compacta formada pela fase e - Fe2-3 (C,N) na superfície das amostras. Resultados menos significativos foram obtidos quando a superfície continha uma mistura de fases contendo g -Fe4 N, e -Fe2-3 N, a -Fe e CrN
Abstract: This work presents a study on the effect of the incorporation of carbon and nitrogen on he formation of a singlephase homogeneous layer, composed by e -Fe2-3(C,N) carbonitrides, on the top surface of a AISI H13 tool steel. We also present studies on the effect of the incorporation of these elements (C and N) in the microstructure and in the mechanical and chemical properties of the surface of the metallic alloy. The incorporation of these elements in the surface of the material was made using the plasma nitrocarburizing termochemical treatment in atmospheres containing N2 + H2+CH4 in different ratios. Beyond the composition of the treatment atmosphere, the temperature and the time of treatment had been also varied. In way to complement the study of the behavior of the metallic alloy we had been also prepared samples with oxidating atmospheres containing CO2. The chemical composition analysis of the sample¿s surface was made through X-ray photo-electron spectroscopy and pointed that nitrogen incorporation suffers great influence from the amount of gas containing carbon, on the plasma atmosphere. However the incorporation of these elements is not directly proportional to the concentration of the gas containing this element. In con-trast, increasing enough the concentration of these elements in the treatment atmosphere, it does not cause increase in the concentration of the same element in the material¿s surface. On the other hand the X-ray diffraction analysis showed the formation of crystalline structures, consistent with the phase diagram of Fe-C-N system. For lesser carbon concentrations in the plasma, the formation of nitrides and carbides are predominant whereas bigger amounts of this element lead to the formarion of the cementite phase (q -Fe3 C , undesirable for possessing low resistance mechanics). The mechanical properties of the surface had been studied by means of nano and microhardness and its results indicate that, as expected, samples with bigger amount of incorporated nitrogen possesses bigger hardness in its surface. This behavior is in agreement with the observed microstructure observed by scanning electron microscopy that show the interlacement of the grains of the steel structure and the fulfilling of its boundaries with iron carbonitrides that make it difficult the movement of the crystalline plans of the lattice increasing its hardness. It was verified that the nitrogen and carbon concentrations in the material¿s surface, are of great influence on the reactivity of the surface regarding to corrosive processes in clorine solutions. This behavior was verified by measurements of corrosion in NaCl aqueous solution. Again the results pointed that bigger nitrogen concentration is responsible for protecting the surface against corrosion process. These results are attributed to the presence of a compact and homogeneous e -Fe2-3(C,N) surface layer on the surface of the samples. Less significant results had been gotten when the surface contained a mixture of phases containing g -F e4N, e -Fe2-3 N, a -Fe e CrN
Doutorado
Física da Matéria Condensada
Doutor em Ciências

Estilos ABNT, Harvard, Vancouver, APA, etc.

Teses / dissertações sobre o tema "Plasma immersion ion implantation"

Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos