Dissertations / Theses on the topic 'Focused Ion Beam machining'
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Evans, R. "Focused ion beam machining of hard materials for micro engineering applications." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/4417.
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The Focused Ion Beam (FIB) milling of single crystal diamond was investigated and the beam drift and mill yield were quantified. The effect of water assistance on the milling of diamond was found to double the yield. The surface morphology that spontaneously forms during milling was measured and the mechanisms behind its formation investigated. The effect of gallium implantation on the diamond crystal structure was measured by x-ray diffraction. Chemical vapour deposited polycrystalline diamond (PCD) has been machined into micro scale turning tools using a combination of laser processing and FIB machining. Laser processing was used to machine PCD into rounded tool blanks and then the FIB was used to produce sharp cutting edges. This combines the volume removal ability of the laser with the small volume but high precision ability of the FIB. Turning tools with cutting edges of 39µm and 13µm were produced and tested by machining micro channels into oxygen free high conductivity copper (OFHCC). The best surface quality achieved was 28nm Sq. This is compared to a Sq of 69nm for a commercial PCD tool tested under the same circumstances. The 28nm roughness compares well to other published work that has reported a Ra of 20nm when machining OFHCC with single crystal diamond tools produced by FIB machining. The time taken to FIB machine a turning tool from a lasered blank was approximately 6.5 hours. Improvements to the machining process and set up have been suggested that should reduce this to ~1 hour, making this a more cost effective process. PCD tools with sinusoidal cutting prongs were produced using FIB. The dimensions of the prongs were less than 10µm. The tools were tested in OFHCC and the prongs survived intact. Changes to the machining conditions are suggested for improved replication of the prongs into metal. Sapphire was FIB machined to produce nano and micro patterns on a curved surface. The sapphire is part of a micro injection mould for replication of polymer parts. The comparative economics of hot embossing and injection moulding have been studied. Injection moulding was found to be the more cost effective process for making polymer parts at commercial production levels.
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Chitsaz, Charandabi Sahand. "Development of a Lorentz force drive system for a torsional paddle microresonator using Focused Ion Beam machining." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4872/.
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This thesis focuses on the concept, design, fabrication and characterisation of a torsional micro paddle resonator. The ultimate intention is to use the device for rapid detection of anthrax bacteria. A comprehensive research was carried out to review the state of the art in MEMS based mass sensing. Various driving and detection strategies were investigated and discussed. Based on evidence from literature, a novel approach was adopted to realise a device with improved functionality and overcome currently existing drawbacks. The working principle of the proposed device is based on electromagnetic actuation and monitoring of the shift in resonance frequency of a micro paddle. The design of the paddle was optimised using theoretical and finite element methods. Dual beam Focused Ion Beam (FIB) machining techniques were used to fabricate the prototype devices. The chosen substrate is a LPCVD 200 nm thick silicon nitride membrane. Prior to milling the substrate, the sputtering rate of silicon nitride was validated experimentally to ensure machining stability. Different actuating pattern designs were fabricated to generate torque including micro spiral coil, micro dual loop, and single conductive track on the micro paddle. The geometry was finalised for a defined working condition of 1 MHz resonance frequency. Important fabrication parameters were discussed and damage prevention issues were investigated. The sensitivity to the added mass was experimentally characterised and found to be 2.35 fg/Hz. To characterise the asymmetrical paddle resonator, piezoelectric excitation was applied to the device and a laser Doppler vibrometer was used to record the resonant frequency. Resonant frequencies of 0.841 and 0.818 MHz were detected by testing the device in an air medium and a quality factor of about 300 was calculated by applying a Lorentzian curve fit to collected data.
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Zhang, Haoyu. "Application of focused ion beam for micro-machining and controlled quantum dot formation on patterned GaAs substrate." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/6408/.
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This project is a study based on the application of focused ion beam (FIB) instrumentation, which has been widely used in fields such as electronic engineering, materials science, semiconductor technology and nanotechnology. We used a Ga+ source focused ion beam column from Orsay Physics mounted on a JEOL 6500F scanning electron microscopy, which forms a SEM-FIB dual-beam instrument. This project consists of a few experimental projects based on the applications of the FIB in electronic engineering. The experimental work will demonstrate the micro-machining capability of the FIB system. The projects include the TEM/STEM cross-sectional sample preparation and the fabrication of a ring shaped aperture and a coded aperture for (S)TEM imaging. The major project is to study InAs quantum dots grown on a FIB patterned GaAs (100) substrate, in order to produce regular arrays of quantum dots at specific sites. In(Ga)As quantum dots have been a very popular topic in electronic engineering for a long time. InGaAs quantum dots have an energy band gap between 0.66eV and 1.41eV, covering the range from infrared (IR) to visible light, which can be used for constructing infrared detectors, solar cells and etc. Regular quantum dot arrays are expected to have better size distribution and high uniformity over a small area with respect to randomly located self-assembled quantum dots, which results in better opto-electronic performance. Overgrowth of a FIB patterned substrate is one of the techniques to produce regular quantum dot arrays. Island-shaped quantum dots are nucleated at specific locations where the ion beam has formerly patterned the surface. Different ion beam patterning parameters are compared and optimized, including accelerating voltage, probe current, dwell time, pitch, growth temperature and thickness of deposited InAs. We have determined the range of the ion beam parameters and the overgrowth conditions, which consistently produce regular quantum dot arrays at the patterned areas without nucleation outside the patterned areas. The relationship between the size of the formed islands and the patterning parameters is investigated by analysing SEM images and AFM images. Micro-photoluminescence and TEM EDX analysis are applied to study the islands formed, to find out the optoelectronic performance and the chemical composition.
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Castro, Olivier de. "Development of a Versatile High-Brightness Electron Impact Ion Source for Nano-Machining, Nano-Imaging and Nano-Analysis." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS468/document.
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Les nano-applications utilisant des faisceaux d'ions focalisés nécessitent des sources d'ions à haute brillance avec une faible dispersion en énergie (ΔE) ce qui permet une excellente résolution latérale et un courant d'ions suffisamment élevé pour induire des vitesses d'érosion raisonnables et des rendements élevés d'émission électronique et ionique. Les objectifs de cette thèse sont le développement d'une source d'ions basée sur l'impact électronique ayant une brillance réduite Br de 10³ – 10⁴ A m⁻² sr ⁻ ¹ V⁻ ¹, une dispersion en énergie ΔE ≲ 1 eV et un choix polyvalent d'ions. Le premier concept évalué consiste à focaliser un faisceau d'électrons à une énergie de 1 keV entre deux électrodes parallèles distant de moins d'un millimètre. Le volume d'ionisation « micrométrique » est formé au-dessus d'une ouverture d'extraction de quelques dizaines de µm. En utilisant un émetteur d'électrons LaB₆ et une pression de 0.1 mbar dans la région d'ionisation, Br est proche de 2.10² A m⁻² sr ⁻ ¹ V ⁻ ¹ avec des tailles de source de quelques µm, des courants de quelques nA pour Ar⁺/Xe⁺/O₂ ⁺ et une dispersion en énergie ΔE < 0.5 eV. La brillance réduite Br est encore en dessous de la valeur minimum de notre objectif et la pression de fonctionnement très faible nécessaire pour l'émetteur LaB₆ ne peut être obtenue avec une colonne d'électrons compacte, donc ce prototype n'a pas été construit.Le deuxième concept de source d'ions évalué est basé sur l’idée d’obtenir un faisceau ionique à fort courant avec une taille de source et un demi-angle d’ouverture similaire aux résultats du premier concept de source, mais en changeant l’interaction électron-gaz et la collection des ions. Des études théoriques et expérimentales sont utilisées pour l’évaluation de la performance de ce deuxième concept et de son utilité pour les nano-applications basées sur des faisceaux d'ions focalisésHigh brightness low energy spread (ΔE) ion sources are needed for focused ion beam nano-applications in order to get a high lateral resolution while having sufficiently high ion beam currents to obtain reasonable erosion rates and large secondary electron/ion yields. The objectives of this thesis are: the design of an electron impact ion source, a reduced brightness Br of 10³ – 10⁴ A m⁻² sr⁻ ¹ V⁻ ¹ with an energy distribution spread ΔE ≲ 1 eV and a versatile ion species choice. In a first evaluated concept an electron beam is focussed in between two parallel plates spaced by ≲1 mm. A micron sized ionisation volume is created above an extraction aperture of a few tens of µm. By using a LaB₆ electron emitter and the ionisation region with a pressure around 0.1 mbar, Br is close to 2.10² A m⁻² sr ⁻ ¹ V ⁻ ¹ with source sizes of a few µm, ionic currents of a few nA for Ar⁺/Xe⁺/O₂ ⁺ and the energy spread being ΔE < 0.5 eV. The determined Br value is still below the minimum targeted value and furthermore the main difficulty is that the needed operation pressure for the LaB₆ emitter cannot be achieved across the compact electron column and therefore a prototype has not been constructed. The second evaluated source concept is based on the idea to obtain a high current ion beam having a source size and half-opening beam angle similar to the first concept, but changing the electron gas interaction and the ion collection. Theoretical and experimental studies are used to evaluate the performance of this second source concept and its usefulness for focused ion beam nano-applications
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Latif, Adnan. "Nanofabrication using focused ion beam." Thesis, University of Cambridge, 2000. https://www.repository.cam.ac.uk/handle/1810/34605.
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Focused ion beam (FIB) technique uses a focused beam of ions to scan the surface of aspecimen, analogous to the way scanning electron microscope (SEM) utilizes electrons. Recent developments in the FIB technology have led to beam spot size below 10 nm,which makes FIB suitable for nanofabrication. This project investigated thenanofabrication aspect of the FIB technique, with device applications perspective inseveral directions. Project work included construction of an in-situ FIB electricalmeasurement system and development of its applications, direct measurements ofnanometer scale FIB cuts and fabrication and testing of lateral field emission devices. Research work was performed using a number of materials including Al, Cr, SiO2, Si3N4and their heterostructures. Measurements performed included in-situ resistometricmeasurements, which provided milled depth information by monitoring the resistancechange of a metal track while ion milling it. The reproducibly of this method wasconfirmed by repeating experiments and accuracy was proven by atomic force microscopy(AFM). The system accurately monitored the thickness of 50 nm wide and 400 nm thick(high aspect ratio) Nb tracks while ion milling them. Direct measurements of low aspectratio nanometer scale FIB cuts were performed using AFM on single crystal Si,polycrystalline Nb and an amorphous material. These experiments demonstrated theimportance of materials aspects for example the presence of grains for cuts at this scale. Anew lateral field emission device (in the plane of the chip) was fabricated, as FIB offersseveral advantages for these devices such as control over sharpness and decrease in anodeto-cathode spacing. FIB fabrication achieved field emission tip sharpness below 50 nm andanode-to-cathode spacing below 100 nm. For determining the field emission characteristicsof the devices, a low current (picoampere) measurement system was constructed anddevices operated in ultra high vacuum (10-9 mbar) in picoampere range. One devicefabricated using a FIB sharpening process had a turn on voltage of 57 V.
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Naik, Jay Prakash. "Nanowires fabricated by Focused Ion Beam." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4638/.
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This thesis reports research on nanowires fabricated by FIB lithography with experiments to understand their mechanical, electrical and hydrodynamic properties. Au nanowires fabricated on Si\(_3\)N\(_4\) membranes with width below 50nm exhibit liquid like instabilities and below \(\sim\)20nm the instabilities grow destroying the nanowires due to the Rayleigh- Plateau instability. Stability is better in the case for Si substrates than for the insulators Si0\(_2\) and Si\(_3\)N\(_4\). A series of 4-terminal resistance measurements were carried out on a "platinum" nanowire grown by FIB-induced decomposition of an organometallic precursor. Such nanowires are found to be a two phase percolating system, containing up to 70% by volume carbon. They have unexpected temperature behaviour which is explained using a percolation model with Kirkpatrick conduction in the presence of temperature induced strain. Au nanowire bridges of very small diameter were probed using AFM to investigate their deformation and fracture strength. Below a diameter \(\sim\)50nm, the mechanical properties are consistent with liquid-like behaviour. After reaching the fracture, the gold molecules from the bridge retract towards the fixed ends; rebinding of the gold causing reforming of the nanowire bridge can occur. FIB fabrication was also used to form a thermal bimorph MEMS cantilever which was investigated by AFM during actuation.
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Wong, Ka Chun. "Focused Ion Beam Nanomachining of Thermoplastic Polymers." Thesis, North Carolina State University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3538536.
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Commercially available Ga+ focused ion beam (FIB) instruments with nanometer size probe allows for in situ materials removal (sputtering) and addition (deposition) on a wide range of material. These spatially precise processes have enabled a wide range of nanofacbrication operations (e.g. specimen preparation for analysis by scanning electron microscope, transmission electron microscope, and secondary ion mass spectrometer). While there exists an established knowledge of FIB methods for sample preparation of hard materials, but FIB methodology remain underdeveloped for soft materials such as biological and polymeric materials.
As FIB is increasingly utilized for specimen preparation of polymeric materials, it is becoming necessary to formulate an information base that will allow established FIB techniques to be generalized to this spectrum of materials. A thorough understanding of the fundamental ion-solid interactions that govern the milling process can be instrumental. Therefore, in an effort to make the existing procedures more universally applicable, the interrelationships between target material, variable processing parameters, and process efficiency of the milling phenomena are examined. The roles of beam current, distance (i.e. step size) between successive FIB beam dwell and the time it spent at each dwell point (i.e. pixel dwell time) are considered as applied to FIB nanomachining of four different thermoplastic polymers: 1. low density polyethylene (LDPE), 2. high density polyethylene (HDPE), 3. Polystyrene (PS), and 4. nylon 6 (PA6). Careful characterization of such relationships is used to explain observed phenomena and predict expected milling behaviors, thus allowing the FIB to be used more efficiently with reproducible results. Applications involving different types of polymer composite fiber are presented.
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Sabouri, Aydin. "Nanofabrication by means of focused ion beam." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5987/.
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Focused ion beam (FIB) systems have been used widely in micro/nano technology due to their unique capabilities. In this fabrication technique, ions are accelerated towards the sample surfaces and substrate atoms are removed. Despite the ubiquity of this method, several problems remain unsolved and are not fully understood. In this thesis, the effects of FIB machining and its halo effects on substrate are investigated. A novel detector which can perform measurements of the current density profile of the generated beam, was successfully demonstrated. The effect of ion solid interactions for 30keV Ga FIB are investigated through atomic force microscopy (AFM) and Raman spectroscopy, for various machining parameters such as current, dwell time and pixel spacing. The FIB implanted regions were also studied for use as a hard mask in plasma etching, and was found to be suitable for high speed patterning in large area fabrication of nano-featured surfaces for metamaterials. It was observed by controlling the implantation parameters, the ultra-thin structures could be made. These structures have wide range of applications such as nano-scale resonators with application of chemical and biological sensing, membranes with nano-pores for DNA translocation and fabrication of near field optical devices.
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Della, Ratta Anthony D. (Anthony David). "Focused ion beam induced deposition of copper." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12418.
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Shedd, Gordon M. 1954. "Focused ion beam assisted deposition of gold." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/14947.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 75-76.
by Gordon M. Shedd.
M.S.
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Wang, H. "Focused-ion-beam growth of nanomechanical resonators." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1417006/.
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Nanoscale mechanical resonators exhibit excellent sensitivity and therefore potential advantages for application as ultrasensitive mass sensors by comparison with micromachined cantilevers. We fabricated three dimensional vertical C-W-nanorods on silicon substrates by focussed ion beam induced deposition (FIB-CVD) and investigated the factors which affected the growth rate and smoothness of the nanorod sidewall, including the heating temperature of precursor gas and the ion beam current. We also discussed the effects on reducing the thickness of the nanorod with FIB milling, including the ion beam current, ion beam energy and ion incident angle. We fabricated a doubly-clamped beam and a singly-clamped beam by felling a vertical nanorod over a trench with FIB milling. We investigated the static mechanical properties (i.e. Young’s modulus) of doubly-clamped and singly-clamped nanorods by atomic force microscopy (AFM) with force displacement measurement. Since the optical signal reflected from a cantilever whose dimensions are sub-wavelength is very weak, it is difficult to measure the absolute nanoscale displacement of such cantilevers with an optical technique. We describe an electron microscope technique for measuring the absolute oscillation amplitude and resonance of nanomechanical resonators with a model-independent method. A piezo-actuator mounted in a field-emission scanning-electron microscope (SEM) is used to excite the nanomechanical resonator to vibrate. The secondary electron signal is recorded as the primary electron beam is scanned linearly over the resonator. An absolute oscillation amplitude as low as 5 nm can be resolved, this being comparable to the size (~1.5 nm) of the primary electron beam. The Q-factor of nanomechanical resonators was measured ranging 300 to 600. The mass resolution of the resonators was also estimated to the level of 1E-15 g.
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Hadfield, Robert Hugh. "Josephson junctions fabricated by focused ion beam." Thesis, University of Cambridge, 2002. https://www.repository.cam.ac.uk/handle/1810/104789.
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This thesis details recent work on an innovative new approach to Josephson junction fabrication. These junctions are created in low TC superconductor-normal metal bilayer tracks on a deep submicron scale using a Focused Ion Beam Microscope (FIB). The FIB is used to mill away a trench 50_nm wide in the upper layer of niobium superconductor (125 nm thick), weakening the superconducting coupling and resulting in a Josephson junction. With the aid of a newly developed in situ resistance measurement technique it is possible to determine the cut depth to a high degree of accuracy and hence gain insight into how this affects the resulting device parameters. Devices fabricated over a wide range of cut depths and copper normal metal layer thicknesses (0-175 nm) have been thoroughly characterized at 4.2 K in terms of current-voltage (I-V) characteristics, magnetic field- and microwave-response. In selected cases I-V characteristics have been studied over the full temperature range from TC down to 300 mK. Devices with resistively-shunted (RSJ) I-V characteristics and ICRN products above 50 μV at 4.2 K have been fabricated reproducibly. This work has been complemented by Transmission Electron Microscopy (TEM) studies that have allowed the microstructure of the individual devices to be inspected and confirm the validity of the in situ resistance measurement. The individual junction devices are promising candidates for use in the next generation of Josephson voltage standards. In collaboration with Dr. Sam Benz at the National Institute of Standards and Technology (NIST) in the U.S., series arrays of junctions have been fabricated and characterized. Phase-locking behaviour has been observed in arrays of 10 junctions of spacings 0.2 to 1.6 μm between 4.2 K and TC in spite of the relatively large spread in individual critical currents. Strategies for minimizing junction parameter spread and producing large-scale arrays are discussed. The opportunities offered by the FIB for the creation of novel device structures has not been overlooked. By milling a circular trench in the Nb Cu bilayer a Corbino geometry SNS junction is created. In this unique device the junction barrier is enclosed in a superconducting loop, implying that magnetic flux can only enter the barrier as quantized vorticies. This gives rise to a startling magnetic field response - with the entry of a vortex the critical current is suppressed from its maximum value to zero. Experimental results and theoretical modeling are reported. Possible future applications of this novel device geometry (which may be of relevance to Quantum Computing and to studies of Berry's phase effects) are considered.
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Moseley, Richard William. "Focused ion beam fabricated non-equilibrium superconducting devices." Thesis, University of Cambridge, 2000. https://www.repository.cam.ac.uk/handle/1810/183624.
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The developments over the last decade in Focused Ion Beam (FIB) instrument technology have reached a point where there is sufficient control of an ion beam to make cuts, trenches, and other shapes in a sample on a scale of tens of nanometers. This work concentrates on the use of an FIB instrument for making superconducting devices. It is shown for the first time that planar-bridge (Nb/Cu/Nb) Superconductor/Normalmetal/Superconductor (SNS) junctions can be reliably fabricated using a standard FIB instrument. This is demonstrated by the responses of junctions to microwaves and magnetic fields; the junctions display the appropriate Josephson behaviour demanded by current technological applications. In addition, the reproducibility in junction behaviour (the variation of critical current is approximately 10%) is the best so far observed for this type of junction. The SNS junction fabrication method has been successfully extended for making high-density SNS junction arrays, dc-SQUIDs, and related devices. A simple model is devised to explain the normal-state resistance and critical current of a junction. The model is based on the geometry of a junction as defined by the FIB instrument and the film deposition. The model is mostly successful in qualitatively explaining many of the geometrical factors that affect the electrical properties of the junction. Nb/Cu/Nb junction series arrays, made using an FIB instrument, are also successfully fabricated. The yield of the junctions forming small arrays is found to be similar to the yield of single junctions. For the series arrays studied here, new observations have been made: the electrical properties of an array have been found to be dependent on the spacing of the junctions and the number of junctions in the array. This work also investigates the thermal properties of SNS and micron-scale superconductor/insulator/normal-metal junction based devices for use in bolometer device based applications. It is shown that self-heating raises the temperature of the junctions significantly above their operating temperatures. For a device sitting on a low thermally conductive membrane, it is found that the effects of heating, or cooling, in the junctions are exaggerated.
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Perez, Martinez Carla S. (Carla Sofia). "Characterization of ionic liquid ion sources for focused ion beam applications." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82506.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2013.This thesis was scanned as part of an electronic thesis pilot project.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 79-82).
In the Focused Ion Beam (FIB) technique, a beam of ions is reduced to nanometer dimensions using dedicated optics and directed to a substrate for patterning. This technique is widely used in micro- and nanofabrication for etching, material deposition, microscopy, and chemical surface analysis. Traditionally, ions from metals or noble gases have been used for FIB, but it may be possible to diversify FIB applications by using ionic liquids. In this work, we characterize properties of an ionic liquid ion source (ILIS) relevant for FIB and recommend strategies for FIB implementation. To install ILIS in FIB, it is necessary to demonstrate single beam emission, free of neutral particles. Beams from ILIS contain a fraction of neutral particles, which could be detrimental for FIB as they are not manipulated by ion optics and could lead to undesired sample modification. We estimate the neutral particle fraction in the beam via retarding potential analysis, and use a beam visualization tool to determine that most of the neutral population is located at the center of the beam; the neutral population might then be eliminated using filtering. The same instrument is used to determine the transition of the source from single to multiple beam emission as the extraction voltage is increased. These studies should guide in the design of the optical columns for an ILIS-based FIB.
by Carla S. Perez Martinez.
S.M.
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Bischoff, Lothar, and Jochen Teichert. "Focused Ion Beam Sputtering of Silicon and Related Materials." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-30797.
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The impressive development of focused ion beam (FIB) systems from the laboratory level to high performance industrial machines during the last twenty years is briefly reported. The design and the functional principle of a liquid metal ion source as well as a FIB column are described. Main application fields of the FIB technology are stoichiometric writing implantation or ion milling which are dominated by the sputtering effect. The FIB is a very suitable tool for sputtering of well defined holes which can easily be analysed by surface profiling. By applying this volume loss method the sputtering yields and milling rates of crystalline, amorphous, and poly-silicon, as well as SiO2, CVD- and high pressure (HP) - diamond and 6H:SiC were investigated for 35 and 70 keV Co, Ga, Ge, Nd and Au ions. For crystalline silicon and 6H:SiC targets, the sputtering yield was determined as a function of the incident angle of the ions and the substrate temperature. In addition, the influence of the pixel dwell time on the erosion process in the case of high dose cobalt implantation was investigated. The experimental obtained yield data are compared with calculated values using different known models.
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Hung, Wen-Chang. "Applications of a high resolution focused ion beam system." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531112.
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Funatsu, Jun. "Laser-assisted focused-ion-beam-induced deposition of copper." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/32617.
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See, Un Siong Patrick. "In-situ focused ion beam patterned resonant tunnelling diodes." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624475.
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Bischoff, Lothar, and Jochen Teichert. "Focused Ion Beam Sputtering of Silicon and Related Materials." Forschungszentrum Rossendorf, 1998. https://hzdr.qucosa.de/id/qucosa%3A21906.
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The impressive development of focused ion beam (FIB) systems from the laboratory level to high performance industrial machines during the last twenty years is briefly reported. The design and the functional principle of a liquid metal ion source as well as a FIB column are described. Main application fields of the FIB technology are stoichiometric writing implantation or ion milling which are dominated by the sputtering effect. The FIB is a very suitable tool for sputtering of well defined holes which can easily be analysed by surface profiling. By applying this volume loss method the sputtering yields and milling rates of crystalline, amorphous, and poly-silicon, as well as SiO2, CVD- and high pressure (HP) - diamond and 6H:SiC were investigated for 35 and 70 keV Co, Ga, Ge, Nd and Au ions. For crystalline silicon and 6H:SiC targets, the sputtering yield was determined as a function of the incident angle of the ions and the substrate temperature. In addition, the influence of the pixel dwell time on the erosion process in the case of high dose cobalt implantation was investigated. The experimental obtained yield data are compared with calculated values using different known models.
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Li, Libing. "Strategies for secondary ion yield enhancements in focused ion beam secondary ion mass spectrometry." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/11806.
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Turnbull, Susan B. "Characterisation of focused ion beam nanostructures by transmission electron microscopy." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/572/.
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Ion irradiation is an effective tool for the modifcation and control of the properties of magnetic thin films. Basic magnetic properties such as coercivity and local anisotropy direction can be altered in NiFe (Permalloy) films, whilst for Co/Pd multilayers, ion irradiation results in a transition from perpendicular to in-plane magnetisation. This ability to tailor magnetic properties in a controlled manner can be used as a tool for nanoscale patterning. Results are presented from investigations into the effect of Ga+ ion dose on the magnetic and structural properties of permalloy thin film systems. Systems consisting of a permalloy layer of either 10nm or 20nm, and one or more non-magnetic layers of Al or Au were deposited by thermal evaporation and irradiated in a focused ion beam (FIB) with a 30kV Ga ion source. The presence of the non-magnetic layers allows irradiation induced mixing with the magnetic layer, effectively creating alloyed regions with different properties to the rest of the film. At low ion doses, no signifcant effect on either the magnetic or structural properties were observed. Bright field TEM images of the irradiated regions revealed that increasing the dose to 1x10^15 ions/cm^2 and above caused an increase in mean grain size from ~5nm to ~30nm. The Fresnel mode of Lorentz microscopy revealed that a reduction in the mean moment was also observed at these doses but no clear changes in coercivity or magnetisation reversal behaviour were observed until the systems were rendered non-magnetic. This occurred at 1x10^16 and 3x10^16 ions/cm^2 for systems with 10nm NiFe and 20nm NiFe respectively. Milling of the samples was evident at these high doses, meaning that it was not possible to magnetically pattern these systems without occasioning a change of 2nm and 6nm respectively in the thickness of the samples. Based on the above, structures were created to control the location of magnetic domain walls (DW). Lines were written by FIB in simple elements with dimensions <1micron, the aim being to create a higher density of DW than could be realised in equivalent homogeneous elements. Structures containing high DW densities are attractive for measuring domain wall magnetoresistive effects and have potential application in DW-based storage or logic devices. One geometry of interest is an element with `zigzag' edges. Results are be presented in chapter 4 showing how these can support either quasi-uniform magnetisation or multi-domain structures separated by DW with spacing <100nm. In chapter 5 irradiation of magnetic structures was again carried out, but this time in magnetic wires to create defect or pinning sites. Domain wall traps fabricated by ion irradiation were characterised, and irradiation line defects introduced along the wire. The lines were patterned at 90± and 45± to the length of the wire, and successfully pinned the domain walls at predefned locations. A 90 degree line irradiated at a dose of 1x10^15 ions/cm^2 was not able to provide a strong enough pinning site for a domain wall. However, when the angle of the line was changed to ±45 degrees it was possible to reproducibly pin domain walls at these sites. A relationship between the orientation of the irradiated line and the chirality of the domain wall that pinned at the site was observed. The effcts of irradiation on Co/Pd multilayers with perpendicular magnetic anisotropy was investigated in chapter 6. Irradiation causes magnetic systems with perpendicular magnetisation to undergo a transition from out-of-plane magnetisation to in-plane. A grid pattern was devised so that magnetic states with both in-plane and out-of-plane magnetisation could be observed. A combination of differential phase contrast microscopy and simulations of integrated magnetic induction were used to determine the orientation of magnetisation within the lines.
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Wang, Xiaohu, and 王小虎. "Optical studies of focused ion beam fabricated GaN microstructures andnanostructures." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47153428.
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In this thesis, Gallium Nitride (GaN) micro- and nanostructures were fabricated based on focused ion beam (FIB) milling. The starting wafer is an epitaxial structure containing InGaN/GaN multi-quantum wells. High crystal quality structures such as the nano-cone, nanopillar array and single pillar were fabricated based on the FIB method. During the fabrication process, various approaches were designed to minimize FIB damage caused by Gallium ion bombardment.
The fabrication process for nano-cone is a combination of mask preparation by FIB with subsequent reactive ion etching (RIE). For fabricating nanopillar arrays, the nanopillars were patterned directly using FIB with an optimized beam current followed by wet etching process to remove the damage. On the other hand, the single pillar is achieved by gradually decreasing the ion beam current as the diameter of the pillar becomes smaller.
The first order Raman spectra for the nanopillar array reveal a strong additional peak when the diameter of the nanopillars is less than 220 nm. This peak can also be observed in GaN pillars without MQW and is clearly assigned to the surface optical (SO) mode originated from the A1 phonon in wurtzite GaN. The frequency of this SO mode is found to be sensitive with the diameter and surface roughness of the nanopillars. Temperature-variable photoluminescence (PL) measurements show that a broadband emission in the as-grown sample split into the two well-resolved bands for nanopillars and the emission band at the higher energy side quickly thermally quenched.
Room temperature PL measurements on the single pillars exhibit an increasing blue-shift of the peak emission with the decreasing of the pillar diameter. Additional simulation data and excitation power dependent PL studies confirm the observation of strain relaxation in the pillar’s MQW due to FIB fabrication. The temperature variable PL on the single pillar shows a monotonous blue shift as the temperature arises to 300 K.published_or_final_version
Electrical and Electronic Engineering
Master
Master of Philosophy
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McGrouther, Damien R. "Effects of focused ion beam irradiation on thin ferromagnetic films." Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410644.
Full text
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Yasaka, Anto. "Feasibility study of spatial-phase-locked focused-ion-beam lithography." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/32663.
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Tian, Zhipeng. "Nanopore/Nanotube Pattern Formation through Focused Ion Beam Guided Anodization." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/46207.
Full textAbstract:
Anodization is a kind of method that can produce oxide layer in a large area and on flexible shaped metals. In some specific conditions, anodic oxide layers exhibit interesting nanopore/nanotube structures. In this work, focused ion beam patterning method is introduced to general anodization, aiming to make highly ordered anodic porous alumina and titania nanotubes.
Focused ion beam guided porous anodic alumina is carried out by pre-designing hexagonal and square guiding patterns with different interpore distances on well electropolished Al foil before anodization. After anodization, the guiding interpore distance is found to affect the new poresâ locations and shapes. Two important elements, electrical field and mechanical stress, are discussed for the development of the guiding pores and the generation of new pores. Based on the proposed pore growth mechanism, novel patterns, non-spherical pores, and large patterns across the grain boundaries are successfully produced.
The research on focused ion beam guided anodic titania nanotubes begins with surface polishing. The influence of four polishing conditions, as-received, chemically polished, mechanically polished, and electropolished samples, are investigated. A polished smooth sample provides a desired surface for focused ion beam guided anodization. Hexagonal guiding patterns with different interpore distances are created on Ti surface. Ordered nanotube arrays are produced, and the structure of the anodized guiding pattern is identified.Master of Science
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CHENG, JI. "FOCUSED ION BEAM FABRICATION OF PHOTONIC STRUCTURES FOR OPTICAL COMMUNICATIONS." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1023127713.
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CHYR, YEONG-NING. "THE PHOTONIC APPLICATIONS OF FOCUSED ION BEAM MICROMACHINGING ON GaN." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin987430536.
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Hadjikhani, Ali. "Nanofabrication and Spectroscopy of Magnetic Nanostructures Using a Focused Ion Beam." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2536.
Full textAbstract:
This research used a focused ion beam in order to fabricate record small nano-magnetic structures, investigate the properties of magnetic materials in the rarely studied range of nanometer size, and exploit their extraordinary characteristics in medicine and nano-electronics. This study consists of two parts: (i) Fabrication and study of record small magnetic tunnel junctions (ii) Introduction of a novel method for detection of magnetoelectric nanoparticles (MENs) in the tissue.
A key challenge in further scaling of CMOS devices is being able to perform non-volatile logic with near zero power consumption. Sub-10-nm nanomagnetic spin transfer torque (STT) magnetic tunneling junctions (MTJs) have the potential for a universal memory that can address this key challenge. The main problem is to decrease the switching current density. This research studied these structures in sub-10-nm size range. In this range, spin related excitations consume considerably smaller amounts of energy as compared to the larger scale. This research concluded that as predicted a decrease in switching current superior to that of the linear scaling will happen in this size range.
Magneto-electric nanoparticles (MENs) can be used to directly couple intrinsic electric-field-driven processes with external magnetic fields for controlling neural activity deep in the brain. These particles have been proven to be capable of inducing deep brain stimulation non-invasively. Furthermore, these magneto-electric nano-particles can be used for targeted drug delivery and are contenders to replace conventional chemotherapy. The circulatory system can deliver a drug to almost every cell in the body; however, delivering the drug specifically into the tumor cell and then releasing it on demand remains a formidable task. Nanomedicine can accomplish this, but ensuring that the drug is released at an appropriate rate once at the target site is an important task. In order to have a complete understanding of the behavior of these MENs when injected into the body, a comprehensive bio-distribution study was performed. This study introduced a novel spectroscopy method for tracing the nanoparticles in the bloodstream. This study investigated the post injection distribution of the MENs in vital organs throughout a period of two months.
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Hussain, Tahir. "Novel impurity distributions in GaAs devices by focused ion beam implantation." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241086.
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Velkova, Valentina. "Focused ion beam technology : implementation in manufacturing platforms and process optimisation." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/10352/.
Full textAbstract:
Process chains are regarded as viable manufacturing platforms for the production of Microand Nano Technology (MNT) enabled products. In particular, by combining several manufacturing technologies, each utilised in its optimal process window, they could benefit from the unique advantages of high-profile research technologies such as the focused ion beam (FIB) machining. The present work concerns the development of process chains and the investigation of pilot cost-effective implementations of the FIB technology in manufacturing platforms forfabrication of serial replication masters.
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Cooper, D. "Off-axis electron holography of focused ion beam prepared semiconductor devices." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597966.
Full textAbstract:
Off-axis electron holography promises to fulfill the requirements of the semiconductor industry for a technique that can be used to provide quantitative information about dopant potentials in semiconductors with nanometer spatial resolution. The technique involves using an electron biprism in a transmission electron microscope (TEM) to interfere a coherent electron wave that has passed through a specimen with a reference wave that has passed only through vacuum. The focused-ion-beam (FIB) miller is the preferred method of sample preparation for semiconductor TEM analysis. In the FIB, a 30kV Ga ion beam is used to thin the specimen in the region of interest. It is increasingly recognised that this method of TEM specimen preparation and subsequent treatments have a profound influence on the phase shifts measured from doped semiconductors. In addition to the effect on the phase shift of surface depletion resulting from the presence of the specimen surfaces, the electrostatic potential in the specimen may be affected by the combined effects of oxidation, physical damage and the implantation of ions such as Ar and Ga during preparation of the sample for electron microscopy, as well as by the effects of irradiation by high-energy electrons during examination in the TEM. Semiconductor specimens have been prepared for examination using electron holography by combining advanced sample preparation techniques such as annealing and Ar ion milling in order to assess the effect of these treatments on the measured phase shifts across the junctions.
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Philipp, Peter. "Phase transformation in tetrahedral amorphous carbon by focused ion beam irradiation." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-136547.
Full textAbstract:
Ion irradiation of tetrahedral amorphous carbon (ta-C) thin films induces a carbon phase transformation from the electrically insulating sp3 hybridization into the conducting sp2 hybridization. In this work, a detailed study on the electrical resistivity and the microstructure of areas, irradiated with several ion species at 30 keV energy is presented. Continuous ion bombardment yields a drastic drop of the resistivity as well as significant structural modifications of the evolving sp2 carbon phase. It is shown that the resistivity lowering can be attributed to the degree of graphitization in the film. Furthermore, the structural ordering processes are correlated with the ion deposited energy density. It is therefore revealed that the ion-induced phase transformation in ta-C films is a combination of sp3-to-sp2 conversion of carbon atoms and ion-induced ordering of the microstructure into a more graphite-like arrangement. All experiments were done with focused ion beam (FIB) systems by applying FIB lithography of electrical van-der-Pauw test structures. FIB lithography on ta-C layers is presented as a fast and easy technique for the preparation of electrically active micro- and nanostructures in an insulating carbon matrix.
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Su, Jong Hea Roland. "An analytical and fundamental study of focused ion beam optical spectroscopy." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388042.
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Sun, Jining. "Deterministic fabrication of micro- and nano-structures by focused ion beam." Thesis, Heriot-Watt University, 2012. http://hdl.handle.net/10399/2528.
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Neusser, Gregor [Verfasser]. "Advanced focused ion beam methods for prototyping and analytical applications / Gregor Neusser." Ulm : Universität Ulm, 2018. http://d-nb.info/1173791051/34.
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Vijendran, Sanjay. "Fabrication of three-dimensional semiconductor devices using focused ion molecular beam epitaxy." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621997.
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Lee, Boon Kwee. "OPTICAL STORAGE IN ERBIUM DOPED GALLIUM NITRIDE USING FOCUSED ION BEAM NANOFABRICATION." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin985883067.
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Luxmoore, Issac J. "Micro-electronic device fabrication using advanced focused ion beam and related techniques." Thesis, University of Sheffield, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489138.
Full textAbstract:
In order to rapidly prototype novel devices with nanoscale precision, new fabrication techniques which can provide high resolution and a quick tum-around are increasingly important in research and development. The focused ion beam (FIB) system is one such instrument and provides the user with the ability to both remove and deposit material with sub lOOnm accuracy without the need for a mask or resist. In this work, focused ion beam technology has been assessed as a technique for prototype microelectronic device fabrication in three main areas.
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Puretz, Joseph. "A theoretical and experimental study of liquid metal ion sources and their application to focused ion beam technology /." Full text open access at:, 1988. http://content.ohsu.edu/u?/etd,182.
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Becherer, Markus [Verfasser]. "Nanomagnetic Logic in Focused Ion Beam Engineered Co/Pt Multilayer Films / Markus Becherer." Aachen : Shaker, 2011. http://d-nb.info/1072592673/34.
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Collins, Clair Louise. "Analytical electron microscopy of HSLA steels prepared using a focused ion beam system." Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412940.
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Sargent, Laurence John. "Performance enhancement in vertical-cavity surface-emitting lasers using focused ion beam etching." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269231.
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Yuan, Hui. "3D morphological and crystallographic analysis of materials with a Focused Ion Beam (FIB)." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0134/document.
Full textAbstract:
L’objectif principal de ce travail est d’optimise la tomographie par coupe sériée dans un microscope ‘FIB’, en utilisant soit l’imagerie électronique du microscope à balayage (tomographie FIB-MEB), soit la diffraction des électrons rétrodiffusés (tomographie dite EBSD 3D). Dans les 2 cas, des couches successives de l’objet d’étude sont abrasées à l’aide du faisceau ionique, et les images MEB ou EBSD ainsi acquises séquentiellement sont utilisées pour reconstruire le volume du matériau. A cause de différentes sources de perturbation incontrôlées, des dérives sont généralement présentes durant l'acquisition en tomographie FIB-MEB. Nous avons ainsi développé une procédure in situ de correction des dérives afin de garder automatiquement la zone d'intérêt (ROI) dans le champ de vue. Afin de reconstruction le volume exploré, un alignement post-mortem aussi précis que possible est requis. Les méthodes actuelles utilisant la corrélation-croisée, pour robuste que soit cette technique numérique, présente de sévères limitations car il est difficile, sinon parfois impossible de se fier à une référence absolue. Ceci a été démontré par des expériences spécifiques ; nous proposons ainsi 2 méthodes alternatives qui permettent un bon alignement. Concernant la tomographie EBSD 3D, les difficultés techniques liées au pilotage de la sonde ionique pour l'abrasion précise et au repositionnement géométrique correct de l’échantillon entre les positions d'abrasion et d’EBSD conduisent à une limitation importante de la résolution spatiale avec les systèmes commerciaux (environ 50 nm)3. L’EBSD 3D souffre par ailleurs de limites théoriques (grand volume d'interaction électrons-solide et effets d'abrasion. Une nouvelle approche, qui couple l'imagerie MEB de bonne résolution en basse tension, et la cartographie d'orientation cristalline en EBSD avec des tensions élevées de MEB est proposée. Elle a nécessité le développement de scripts informatiques permettant de piloter à la fois les opérations d’abrasion par FIB et l’acquisition des images MEB et des cartes EBSD. L’intérêt et la faisabilité de notre approche est démontrée sur un cas concret (superalliage de nickel). En dernier lieu, s’agissant de cartographie d’orientation cristalline, une méthode alternative à l’EBSD a été testée, qui repose sur l’influence des effets de canalisation (ions ou électrons) sur les contrastes en imagerie d’électrons secondaires. Cette méthode corrèle à des simulations la variation d’intensité de chaque grain dans une série d’images expérimentales obtenues en inclinant et/ou tournant l’échantillon sous le faisceau primaire. Là encore, la méthode est testée sur un cas réel (polycritsal de TiN) et montre, par comparaison avec une cartographie EBSD, une désorientation maximale d'environ 4° pour les angles d’Euler. Les perspectives d’application de cette approche, potentiellement beaucoup plus rapide que l’EBSD, sont évoquéesThe aim of current work is to optimize the serial-sectioning based tomography in a dual-beam focused ion beam (FIB) microscope, either by imaging in scanning electron microscopy (so-called FIB-SEM tomography), or by electron backscatter diffraction (so-called 3D-EBSD tomography). In both two cases, successive layers of studying object are eroded with the help of ion beam, and sequentially acquired SEM or EBSD images are utilized to reconstruct material volume. Because of different uncontrolled disruptions, drifts are generally presented during the acquisition of FIB-SEM tomography. We have developed thus a live drift correction procedure to keep automatically the region of interest (ROI) in the field of view. For the reconstruction of investigated volume, a highly precise post-mortem alignment is desired. Current methods using the cross-correlation, expected to be robust as this digital technique, show severe limitations as it is difficult, even impossible sometimes to trust an absolute reference. This has been demonstrated by specially-prepared experiments; we suggest therefore two alternative methods, which allow good-quality alignment and lie respectively on obtaining the surface topography by a stereoscopic approach, independent of the acquisition of FIB-SEM tomography, and realisation of a crossed ‘hole’ thanks to the ion beam. As for 3D-EBSD tomography, technical problems, linked to the driving the ion beam for accurate machining and correct geometrical repositioning of the sample between milling and EBSD position, lead to an important limitation of spatial resolution in commercial softwares (~ 50 nm)3. Moreover, 3D EBSD suffers from theoretical limits (large electron-solid interaction volume for EBSD and FIB milling effects), and seems so fastidious because of very long time to implement. A new approach, coupling SEM imaging of good resolution (a few nanometres for X and Y directions) at low SEM voltage and crystal orientation mapping with EBSD at high SEM voltage, is proposed. This method requested the development of computer scripts, which allow to drive the milling of FIB, the acquisition of SEM images and EBSD maps. The interest and feasibility of our approaches are demonstrated by a concrete case (nickel super-alloy). Finally, as regards crystal orientation mapping, an alternative way to EBSD has been tested; which works on the influence of channelling effects (ions or electrons) on the imaging contrast of secondary electrons. This new method correlates the simulations with the intensity variation of each grain within an experimental image series obtained by tilting and/or rotating the sample under the primary beam. This routine is applied again on a real case (polycrystal TiN), and shows a max misorientation of about 4° for Euler angles, compared to an EBSD map. The application perspectives of this approach, potentially faster than EBSD, are also evoked
44
Llobet, Sixto Jordi. "Focused ion beam implantation as a tool for the fabrication of nano electromechanical devices." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/384934.
Full textAbstract:
La tesi doctoral titulada “Focused ion beam implantation as a tool for the fabrication of nano electromechanical devices” aborda el repte de la fabricació de ressonadors nano-mètrics des d’una nova òptica basada en la implantació iònica mitjançant un feix de ions focalitzat (FIB). Aquest nou mètode permet fabricar nano-dispositius suspesos funcionals, des del punt de vista elèctric i mecànic, sense necessitat d’utilitzar resina d’una forma i) ràpida i simple, només son necessàries tres etapes de fabricació; ii) flexible, permet definir dispositius amb gran llibertat geomètrica; iii) alta resolució, es demostra la fabricació de dispositius suspesos de 4 μm de longitud per 10 nm de diàmetre; iv) reproduïble i v) compatible amb la tecnologia CMOS.
Partint d’un xip de silici o SOI (silici - diòxid de silici - silici), el mètode de fabricació comença amb un procés d’implantació FIB on es defineixen les estructures i les connexions elèctriques del dispositiu. El segon pas consisteix en el gravat humit del silici, on s’ataca el silici que no està protegit per la implantació FIB, permetent la suspensió o alliberació dels dispositius. En aquest estadi, on les estructures ja estan definides, el silici és amorf, conté gal·li i no és elèctricament funcional (ρ ~1 Ω·m). El darrer pas consisteix en un tractament tèrmic a alta temperatura fins a 1000ºC, en ambient de nitrogen i amb un precursor sòlid de bor on es propicia la recristal·lització del silici formant nano-cristalls, dopar el silici amb bor (tipus p) i eliminar el gal·li. Aquest tractament a alta temperatura, on les estructures no son oxidades, permet obtenir dispositius elèctricament funcionals (ρ ~10-4 Ω·m).
Els principals resultats obtinguts es poden classificar en tres àmbits:
Investigació de l’efecte de la implantació amb ions gal·li en el silici, pel que fa tant a aspectes de processament com de propietats nanoelectromecàniques del material.
En aquest treball hem caracteritzat l’estructura del material en les diferents etapes de fabricació i hem caracteritzat elèctrica i electromecànicament els dispositius finals obtinguts pel mètode descrit.
Desenvolupament i optimització del procés de fabricació, especialment pel que respecte al control de dimensions i a la combinació amb altres processos
Es mostra el treball realitzat en la optimització dels diferents paràmetres de fabricació, des de la posta a punt de la dosi d’ions fins a la selectivitat del gravat. A través del disseny de les estructures es pot establir estratègies per controlar i minimitzar els efectes d’”under-etching” en el silici, a través de la definició d’estructures de compensació, i també evitar el col·lapse de les estructures més llargues, degut a les tensions superficials que es produeixen durant els processos de gravat humit, fabricant pilars per sostenir les estructures.
Aquest mètode de fabricació permet obtenir dispositius a mida convertint-lo en una eina versàtil de prototipatge i de fabricació petites quantitats, que permet aconseguir dispositius de dimensions nano-mètriques per a l’experimentació acadèmica i científica.
Investigació de les propietats electròniques, mecàniques i electromecàniques dels dispositius, i concretament en el cas de nanofils de silici suspesos que es poden aplicar com a ressonadors mecànics d’altra freqüència o transistors d’un sol forat.
Hem pogut fabricar ressonadors de diferents geometries que ens ha permès estudiar i demostrar la relació que existeix entre la simetria/asimetria dels dispositius i el senyal piezoresistiu mesurat durant la transducció electromecànica. Hem investigat i fabricat transistors d’efecte camp ultra-fins (10 ~ 15 nm) i transistors suspesos on les característiques elèctriques a baixa temperatura mostren efectes de “Coulomb blockade” gracies als nano-cristalls que es formen, dins dels nano-fils de silici suspesos, durant l’etapa de tractament tèrmic.The thesis entitled “Focused ion beam implantation as a tool for the fabrication of nano electromechanical devices” aboard the challenge of the fabrication of nanometric resonators from a new approach based on ion implantation by a focused ion beam (FIB) . This new method allows the fabrication of functional suspended nanodevices, from the electrical and mechanical point of view, without using any resist. This method is i) fast and simple, where only three steps are needed; ii) flexible, it is feasible the definition of structures of different shape; iii) high resolution, it is demonstrated the fabrication of 4 μm length and 10 nm diameter suspended devices; iv) reproducible and v) CMOS compatible. The starting point is a silicon or SOI (silicon – silicon dioxide – silicon) chip. The fabrication approach starts with a FIB implantation process where the structures and the electrical connections of the device are defined. The second step consists on silicon wet etching, where silicon that is not protected by the FIB implantation is etched, allowing the release of the devices. The defined structures are made of amorphous silicon, they contains gallium and they are not functional electrically (ρ ~1 Ω·m). The last step consists on diffusive boron doping at high temperature (up to 1000ºC) in a boron environment, where it is promoted the recrystallization of silicon forming nanocrystals, the boron doping (p type) of silicon and the removal of gallium. In this last step at high temperature the structures are not oxidized obtaining electrically functional devices (ρ ~10-4 Ω·m). The principal results can be classified in three areas: Investigation of the effect of gallium ion implantation onto silicon from the process and nanoelectromechanical material properties point of view. In this work the material structure in the different fabrication steps has been characterized, as well as the electrical and electromechanical properties of the final devices obtained by the described method. Development and optimization of the fabrication process, especially controlling the dimensions and the combination with other fabrication processes. The work done in the optimization of the different fabrication parameters are shown, from the tuning of the ion dosage to the etching selectivity. It is possible to stablish design strategies to control and minimize the under-etching effects onto silicon, as well as to avoid the collapse of long structures, that are the result of the superficial sticking produced during the wet etching processes, by the fabrication of sustaining posts. That method permits to obtain customized devices. It is a versatile prototyping method that allows the fabrication of small batches of devices of nanometric dimensions that can be employed for the scientific and academic experimentation. Investigation of the electronical, mechanical and electromechanical properties of the devices, specifically suspended silicon nanowires that can be employed as high frequency mechanical resonators or single hole transistors. We fabricated resonators of different geometries for the study and demonstration of the relation between the geometrical symmetry/asymmetry of the devices and the piezoresistive signal measured during the electromechanical transduction. We investigated and fabricated ultra-thin field effect transistors (10 ~ 15 nm) and suspended transistors that exhibits Coulomb blockade electrical characteristics at low temperature thanks to the nanocrystals that are grown during the high temperature fabrication step.
45
Youssef, Amanda. "Three-dimensional defect characterization : focused ion beam tomography applied to tin sulfide thin films." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92112.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 81-86).
Porosity is postulated to be one of the reasons for the low efficiency of tin sulfide-based devices. This work is a preliminary investigation of the effects of two film growth parameters deposition rate and substrate temperature - on porosity. We employ the focused ion beam tomography technique to characterize and quantify porosity in tin sulfide thin films. We then generate 3D reconstructions of pores inside milled volumes from the films and quantify pore volumes. To explain the results, we employ nucleation theory and develop two different models: (a) a thermodynamic model that assumes pores form primarily from an effect known as "self-shadowing," whereby growth-rate anisotropy results in some grains that grow faster than their neighbors, and (b) a kinetic model that assumes a diffusion-driven process of void formation. We show that both models qualitatively support the experimental results, providing insight into process-structure relations that may improve film quality during growth.
by Amanda Youssef.
S.M.
46
Llobet, Sixto Josep. "Focused ion beam implantation as a tool for the fabrication of nano electromechanical devices." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/384934.
Full textAbstract:
La tesi doctoral titulada “Focused ion beam implantation as a tool for the fabrication of nano electromechanical devices” aborda el repte de la fabricació de ressonadors nano-mètrics des d’una nova òptica basada en la implantació iònica mitjançant un feix de ions focalitzat (FIB). Aquest nou mètode permet fabricar nano-dispositius suspesos funcionals, des del punt de vista elèctric i mecànic, sense necessitat d’utilitzar resina d’una forma i) ràpida i simple, només son necessàries tres etapes de fabricació; ii) flexible, permet definir dispositius amb gran llibertat geomètrica; iii) alta resolució, es demostra la fabricació de dispositius suspesos de 4 μm de longitud per 10 nm de diàmetre; iv) reproduïble i v) compatible amb la tecnologia CMOS.
Partint d’un xip de silici o SOI (silici - diòxid de silici - silici), el mètode de fabricació comença amb un procés d’implantació FIB on es defineixen les estructures i les connexions elèctriques del dispositiu. El segon pas consisteix en el gravat humit del silici, on s’ataca el silici que no està protegit per la implantació FIB, permetent la suspensió o alliberació dels dispositius. En aquest estadi, on les estructures ja estan definides, el silici és amorf, conté gal·li i no és elèctricament funcional (ρ ~1 Ω·m). El darrer pas consisteix en un tractament tèrmic a alta temperatura fins a 1000ºC, en ambient de nitrogen i amb un precursor sòlid de bor on es propicia la recristal·lització del silici formant nano-cristalls, dopar el silici amb bor (tipus p) i eliminar el gal·li. Aquest tractament a alta temperatura, on les estructures no son oxidades, permet obtenir dispositius elèctricament funcionals (ρ ~10-4 Ω·m).
Els principals resultats obtinguts es poden classificar en tres àmbits:
Investigació de l’efecte de la implantació amb ions gal·li en el silici, pel que fa tant a aspectes de processament com de propietats nanoelectromecàniques del material.
En aquest treball hem caracteritzat l’estructura del material en les diferents etapes de fabricació i hem caracteritzat elèctrica i electromecànicament els dispositius finals obtinguts pel mètode descrit.
Desenvolupament i optimització del procés de fabricació, especialment pel que respecte al control de dimensions i a la combinació amb altres processos
Es mostra el treball realitzat en la optimització dels diferents paràmetres de fabricació, des de la posta a punt de la dosi d’ions fins a la selectivitat del gravat. A través del disseny de les estructures es pot establir estratègies per controlar i minimitzar els efectes d’”under-etching” en el silici, a través de la definició d’estructures de compensació, i també evitar el col·lapse de les estructures més llargues, degut a les tensions superficials que es produeixen durant els processos de gravat humit, fabricant pilars per sostenir les estructures.
Aquest mètode de fabricació permet obtenir dispositius a mida convertint-lo en una eina versàtil de prototipatge i de fabricació petites quantitats, que permet aconseguir dispositius de dimensions nano-mètriques per a l’experimentació acadèmica i científica.
Investigació de les propietats electròniques, mecàniques i electromecàniques dels dispositius, i concretament en el cas de nanofils de silici suspesos que es poden aplicar com a ressonadors mecànics d’altra freqüència o transistors d’un sol forat.
Hem pogut fabricar ressonadors de diferents geometries que ens ha permès estudiar i demostrar la relació que existeix entre la simetria/asimetria dels dispositius i el senyal piezoresistiu mesurat durant la transducció electromecànica. Hem investigat i fabricat transistors d’efecte camp ultra-fins (10 ~ 15 nm) i transistors suspesos on les característiques elèctriques a baixa temperatura mostren efectes de “Coulomb blockade” gracies als nano-cristalls que es formen, dins dels nano-fils de silici suspesos, durant l’etapa de tractament tèrmic.The thesis entitled “Focused ion beam implantation as a tool for the fabrication of nano electromechanical devices” aboard the challenge of the fabrication of nanometric resonators from a new approach based on ion implantation by a focused ion beam (FIB) . This new method allows the fabrication of functional suspended nanodevices, from the electrical and mechanical point of view, without using any resist. This method is i) fast and simple, where only three steps are needed; ii) flexible, it is feasible the definition of structures of different shape; iii) high resolution, it is demonstrated the fabrication of 4 μm length and 10 nm diameter suspended devices; iv) reproducible and v) CMOS compatible. The starting point is a silicon or SOI (silicon – silicon dioxide – silicon) chip. The fabrication approach starts with a FIB implantation process where the structures and the electrical connections of the device are defined. The second step consists on silicon wet etching, where silicon that is not protected by the FIB implantation is etched, allowing the release of the devices. The defined structures are made of amorphous silicon, they contains gallium and they are not functional electrically (ρ ~1 Ω·m). The last step consists on diffusive boron doping at high temperature (up to 1000ºC) in a boron environment, where it is promoted the recrystallization of silicon forming nanocrystals, the boron doping (p type) of silicon and the removal of gallium. In this last step at high temperature the structures are not oxidized obtaining electrically functional devices (ρ ~10-4 Ω·m). The principal results can be classified in three areas: Investigation of the effect of gallium ion implantation onto silicon from the process and nanoelectromechanical material properties point of view. In this work the material structure in the different fabrication steps has been characterized, as well as the electrical and electromechanical properties of the final devices obtained by the described method. Development and optimization of the fabrication process, especially controlling the dimensions and the combination with other fabrication processes. The work done in the optimization of the different fabrication parameters are shown, from the tuning of the ion dosage to the etching selectivity. It is possible to stablish design strategies to control and minimize the under-etching effects onto silicon, as well as to avoid the collapse of long structures, that are the result of the superficial sticking produced during the wet etching processes, by the fabrication of sustaining posts. That method permits to obtain customized devices. It is a versatile prototyping method that allows the fabrication of small batches of devices of nanometric dimensions that can be employed for the scientific and academic experimentation. Investigation of the electronical, mechanical and electromechanical properties of the devices, specifically suspended silicon nanowires that can be employed as high frequency mechanical resonators or single hole transistors. We fabricated resonators of different geometries for the study and demonstration of the relation between the geometrical symmetry/asymmetry of the devices and the piezoresistive signal measured during the electromechanical transduction. We investigated and fabricated ultra-thin field effect transistors (10 ~ 15 nm) and suspended transistors that exhibits Coulomb blockade electrical characteristics at low temperature thanks to the nanocrystals that are grown during the high temperature fabrication step.
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Rasera, Roy L. (Roy Louis). "Laser linking of metal interconnect : process considerations and failure analysis using focused ion beam milling." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/32180.
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FENG, Zhifu. "Electron Beam Lithography and Focused Ion Beam Techniques for the Development of Low Power Consumption Microelectromechanical Systems-based Chemiresistive Gas Sensors." Doctoral thesis, Università degli studi di Ferrara, 2023. https://hdl.handle.net/11392/2502108.
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I sensori di gas sono ampiamente utilizzati per rilevare gas tossici per la protezione ambientale, il monitoraggio industriale, la sicurezza domestica, l'analisi del respiro e il deterioramento degli alimenti. A parte i sensori di gas elettrochimici, che hanno una breve durata, e i sensori di gas ottici di grandi dimensioni con un costo elevato, i sensori di gas chemiresistivi basati su ossidi metallici semiconduttori (OMS) risultano essere una soluzione tecnologica estremamente interessante, grazie alla sua bassa produzione costo, proprietà fisiche stabili e versatilità chimica. Tuttavia, per via dell'elevata temperatura operativa dei sensori di gas OMS, la riduzione del consumo energetico è di fondamentale importanza per una loro futura integrazione su dispositivi portatili, quali gli smartphones. A tale scopo, la miniaturizzazione dei sensori di gas OMS, principalmente per quanto riguarda il microriscaldatore, che funge da supporto meccanico del materiale di rilevamento e della parte riscaldatore/elettrodo, è un modo efficace per migliorare l'efficienza energetica. I sistemi microelettromeccanici (MEMS) offrono l'opportunità di raggiungere tale obiettivo. Questa dissertazione, focalizzata principalmente alla miniaturizzazione del microriscaldatore, si è concentrata sulla simulazione della dissipazione del calore del microriscaldatore mediante analisi agli elementi finiti, e sulla fabbricazione degli stessi utilizzando la litografia a fascio di elettroni (EBL) e il fascio di ioni focalizzati (FIB) per lo sviluppo di sensori di gas a bassissimo consumo energetico.
Quindi sono stati studiati e utilizzati due diversi approcci presso le strutture della Fondazione Bruno Kessler per fabbricare i microriscaldatori. Il primo metodo ha combinato le tecniche EBL e FIB per definire il layout del riscaldatore stesso. EBL è stato utilizzato per esporre la parte dell'elettrodo di dimensioni micrometriche, mentre il FIB è stato utilizzato per fresare la parte del circuito del riscaldatore con caratteristiche nanometriche. Nel secondo metodo, è stata utilizzata un'esposizione EBL in due fasi, senza utilizzo del FIB: i) bassa energia del fascio di elettroni con bassa dose e ampia area di scrittura per la definizione della struttura degli elettrodi; ii) alta energia del fascio di elettroni con dose elevata e piccolo campo di scrittura per la definizione del circuito del riscaldatore.
Dopo che questi microriscaldatori sono stati fabbricati, le loro proprietà elettriche e termiche sono state valutate sperimentalmente. Successivamente sono stati sviluppati sensori chemiresistivi sfruttando i microriscaldatori sviluppati. In particolare, il nanofilm ZnO di materiale sensibile di tipo n è stato depositato su MHP2 e NHP1 mediante magnetron sputtering. Il SEM ha rivelato le dimensioni nanometriche delle particelle di ZnO. La struttura cristallina di ZnO è stata caratterizzata dalla diffrazione della polvere di raggi X (XRD) e la spettroscopia fotoelettronica a raggi X (XPS) ha dimostrato il rapporto atomico di Zn e O. Il nanofilm di ZnO non ha mostrato una forte risposta all'umidità, mentre ha mostrato una buona sensibilità nei confronti del NO2.
Successivamente, i microriscaldatori MHP1 sono stati testati anche come substrati per sensori chemiresistivi a film spesso, utilizzando come materiale sensibile SnO2 altamente drogate con antimonio (ATO), concentrazione atomica del 10% e 15% in peso. Questi materiali sono stati caratterizzati da SEM, XRD e XPS, il che ha suggerito che il drogaggio di antimonio ha modificato la morfologia rispetto alla polvere di SnO2 non drogata, prevenendo la crescita delle particelle di polvere e diminuendo quindi la dimensione media delle nanoparticelle. La caratterizzazione XPS ha dimostrato che la concentrazione di antimonio era maggiore sulla superficie delle nanoparticelle di SnO2 rispetto al bulk. È stato riscontrato che i sensori ATO hanno portato a un’alta selettività e sensibilità all'NO2.Gas sensors are widely used for detecting toxic gases for environmental protection, industrial monitoring, household safety, breath analysis and food deterioration. Apart from the electrochemical gas sensors, which have a short lifetime, and optical gas sensors with large volume size with high cost, semiconductor metal oxide (SMO) gas sensors as one of the chemiresistive type gas sensors are now developing fast owing to its low production cost, stable physical properties and chemical versatility. However, regarding the high operational temperature of SMO gas sensors, reduction of power consumption is extremely important for its application in smartphones and other portable devices. For this purpose, miniaturization of SMO gas sensor devices, primarily for the hotplate part acting as mechanical support of the sensing material and heater/electrode part, is an effective way to improve the power efficiency. Microelectromechanical systems (MEMS) offer an opportunity to achieve such goal. This dissertation addressed to miniaturization of the hotplate, was focused on hotplate fabrication by using Electron Beam Lithography (EBL) and Focused Ion Beam (FIB). Then two different approaches were studied and used at Bruno Kessler Foundation facilities to microfabricate the hotplates. First method combined EBL and FIB techniques to define the layout. EBL was used to exposure the micro-level size electrode part (or pad part), and FIB was used to mill the heater circuit part with fine and dense structure. The patterned hotplate structure was characterized by Scanning Electron Microscope (SEM), and the milling result was analyzed by Secondary-ion Mass Spectrometry (SIMS). By studying these results, the optimized parameters for EBL and FIB were selected. The second method used two-step EBL exposure. Low energy of electron beam with low dose and large writing field for the electrode part exposure and high energy of electron beam with high dose and small writing field for the dense heater circuit patterning. After these hotplates were fabricated, their electrical and thermal properties were experimentally evaluated. Subsequently, chemiresistive sensors based on the developed hotplates were developed. In particular, n-type sensing material ZnO nano film was deposited on MHP2 and NHP1 by magnetron sputtering technique. SEM revealed the nano size of ZnO particle, and the calcination condition effect on the size of ZnO. ZnO crystal structure was characterized by X-ray Powder Diffraction (XRD), and X-Ray Photoelectron Spectroscopy (XPS) proved the atom ratio of Zn and O. ZnO nanofilm did not show strong response to humidity, but humidity could decrease the response toward NO2, and increase the response toward ethanol. Thick films of SnO2 highly doped by antimony with concentration of 10 wt% (ATO1) and 15wt% (ATO2) were drop coated on MHP1. These materials were characterized by SEM, XRD and XPS. It suggested that antimony doping modified the morphology of SnO2 powder by preventing the growth of powder particles. The results of the XPS experiment demonstrated that the concentration of antimony was higher on the surface of SnO2 than its inside. It was found that ATO sensors led to a particularly high selectivity and sensitivity to NO2 when compared to the other gases at 400 °C in dry air. Additionally, the sensing response of ATO1 and ATO2 was only moderately affected by humidity, which made them ideal candidates to detect NO2 in the actual atmosphere.
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Silva, Marcelo Macchi da. "Micro e nanofabricação (fabricação de contatos eletricos) por feixe de ions focalizados." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259243.
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Orientadores: Jacobus Willibrordus Swart, Stanislav MoshkalevDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: A nanotecnologia e uma área nova e promissora que englobam muitas disciplinas de ciência e engenharia. Seu rápido crescimento nas ultimas duas décadas é devido ao crescimento simultâneo na fabricação e caracterização de materiais em escala nanométrica. O objetivo deste trabalho é desenvolver uma técnica de processo híbrido para a fabricação de micro e nanocontatos assim como sua caracterização elétrica. Esse processo híbrido combina a fotolitografia seguida da técnica de lift-off e a deposição de platina por FIB. Para determinar a resistividade da platina depositada por FIB (Focuded Ion Beam), foram fabricas estruturas quadradas variando sua espessura de 5 nm - 100 nm e sua área 150 µm 150 µm e 20 µm x 20 µm. Resistores com comprimento de 30 µm variando sua área de secção (50 nm x 50 nm - 1 µm x 1 µm) foram fabricados a fim de uma melhor na caracterização do processo de deposição do filme de Pt assim como sua caracterização elétrica. As medidas elétricas foram realizadas na estação Keythley 4200 SCS, onde foi utilizado o método de quatro pontas nas estruturas quadradas para a caracterização da resistividade. Nos resistores utilizamos a configuração de dois terminais para a caracterização de resistência dos nanocontatos.
Abstract: Nanoscale science and technology is a young and burgeoning field that encompasses nearly every discipline of science and engineering, the rapid growth of the field in the past decades has been enable by the sustained advances in the fabrication and characterization of materials. This work presents the hybrid process for fabrication of micro and nanocontacts, this process include the lift - off technique and platinum deposited by FIB. For measurements, two types of test structures were fabricated: (i) 150 x 150 µm and 20 x 20 µm squares with thickness of 5, 10, 30 and 100 nm, and (ii) 30 µm long resistors with variable cross - section (50 nm x 50 nm to 1 µm x 1 µm). The Pt film resistivity has been measured by a four points probe method.
Mestrado
Eletrônica, Microeletrônica e Optoeletrônica
Mestre em Engenharia Elétrica
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Drǎghici, Mihai. "In-plane gate transistors fabricated by focused ion beam implantation in negative and positive pattern definition." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=983711526.
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