Log in

Relevant bibliographies by topics / Silicon oxide / Dissertations / Theses

Dissertations / Theses on the topic 'Silicon oxide'

To see the other types of publications on this topic, follow the link: Silicon oxide.

Author: Grafiati

Published: 4 June 2021

Last updated: 31 July 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Silicon oxide.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Mehonić, Adnan. "Resistive switching in silicon-rich silicon oxide." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1420436/.

Full text

Abstract:

Over the recent decade, many different concepts of new emerging memories have been proposed. Examples of such include ferroelectric random access memories (FeRAMs), phase-change RAMs (PRAMs), resistive RAMs (RRAMs), magnetic RAMs (MRAMs), nano-crystal floating-gate flash memories, among others. The ultimate goal for any of these memories is to overcome the limitations of dynamic random access memories (DRAM) and flash memories. Non-volatile memories exploiting resistive switching – resistive RAM (RRAM) devices – offer the possibility of low programming energy per bit, rapid switching, and very high levels of integration – potentially in 3D. Resistive switching in a silicon-based material offers a compelling alternative to existing metal oxide-based devices, both in terms of ease of fabrication, but also in enhanced device performance. In this thesis I demonstrate a redox-based resistive switch exploiting the formation of conductive filaments in a bulk silicon-rich silicon oxide. My devices exhibit multi-level switching and analogue modulation of resistance as well as standard two-level switching. I demonstrate different operational modes (bipolar and unipolar switching modes) that make it possible to dynamically adjust device properties, in particular two highly desirable properties: non-linearity and self-rectification. Scanning tunnelling microscopy (STM), atomic force microscopy (AFM), and conductive atomic force microscopy (C-AFM) measurements provide a more detailed insight into both the location and the dimensions of the conductive filaments. I discuss aspects of conduction and switching mechanisms and we propose a physical model of resistive switching. I demonstrate room temperature quantisation of conductance in silicon oxide resistive switches, implying ballistic transport of electrons through a quantum constriction, associated with an individual silicon filament in the SiOx bulk. I develop a stochastic method to simulate microscopic formation and rupture of conductive filaments inside an oxide matrix. I use the model to discuss switching properties – endurance and switching uniformity.

APA, Harvard, Vancouver, ISO, and other styles

2

Anthony, Carl John. "Oxide interface studies on silicon and silicon carbide." Thesis, University of Newcastle Upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424150.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Gold, Scott Alan. "Nitrogen incorporation in thin silicon oxide films for passivation of silicon solar cell surfaces." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/11101.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Shah, M. "Excitation mechanisms in erbium-doped silicon-rich silicon oxide." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1420212/.

Full text

Abstract:

Since the invention of the first silicon transistor in 1947, the electronics industry has grown at a rapid rate, famously predicted and guided by Moore’s law. However, it has recently become apparent that satisfying Moore’s law is becoming increasingly difficult; we are now approaching the fundamental limits of device miniaturization and device speed, and alternative solutions for this problem are continuously being pursued. Over the past couple of decades, silicon photonics has emerged as a promising alternative solution. By carrying data through photons instead of electrons, many of the problems faced in an electronic device become irrelevant in an equivalent photonic device. The challenge of silicon photonics is to demonstrate lasing in a material that is compatible with existing CMOS processing technology, namely silicon. Light emission from silicon, however, is very inefficient, due to its indirect electronic bandgap. Silicon nanostructures, on the other hand, exhibit far higher light emission efficiencies, which has been attributed to quantum confinement effects. Erbium is one of the most interesting rare earth impurities for optical functionality, as it emits photons at 1.54µm, the wavelength that corresponds to minimum attenuation in silica fibres. However, erbium has a relatively low excitation cross section, and narrow excitation bands, necessitating expensive lasers for amplifier operation. It has been found that, by co-doping erbium with silicon-nanocrystals (Si-ncs), far higher excitation efficiencies of erbium can be attained, along with broadband excitation, through energy transfer from excited Si-ncs. To date, a clear understanding of the physics involved in the excitation mechanism is lacking. In this thesis, I identify erbium excitation processes in the Er doped silicon rich silicon oxide material, through photoluminescence (PL) spectroscopy. In particular, time resolved decay data of erbium emission is analysed through exponential fitting and rate equation modelling. The significance of Purcell enhanced radiative emission, and Er ion-ion interactions are highlighted. Furthermore, a characterisation study of Er doped silicon rich silicon oxide thin films will be carried out, revealing the significance and differences between defect, Si- nanocluster, and Si-nanocrystal sensitisation of Er ions. The prospects of device fabrication will also be discussed.

APA, Harvard, Vancouver, ISO, and other styles

5

Johnson, Robert Shawn. "Properties of Aluminum Oxide and Aluminum Oxide Alloys and their Interfaces with Silicon and Silicon Dioxide." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-20020122-104946.

Full text

Abstract:

A remote plasma enhanced chemical vapor deposition method, RPECVD, was utilized to deposit thin films of aluminum oxide, tantalum oxide, tantalum aluminates, and hafnium aluminates. These films were analyzed using auger electron spectroscopy, AES, Fourier transform infrared spectroscopy, FTIR, X-ray diffraction, XRD, nuclear resonance profiling, NRP, capacitance versus voltage, C-V, and current versus voltage, J-V. FTIR indicated the alloys were homogeneous and pseudobinary in character. Combined with XRD the crystallization temperatures for films >100 nm were measured. The alloys displayed an increased temperature stability with the crystallization points being raise by >100ºC above the end point values.In-situ AES analysis provided a study of the initial formation of the films' interface with the silicon substrate. For Al2O3 these results were correlated to NRP results and indicated a thin, ~0.6 nm, interfacial layer formed during deposition.C-V characteristics indicated a layer of fixed negative charge associated with Al2O3. For Ta2O5 the C-V and J-V results displayed high levels of leakage current, due to a low conduction band offset with silicon. Both aluminates were dominated by electron trapping states. These states were determined to be due to (i) a network "break-up" component and (ii) localized atomic d-states of hafnium and tantalum atoms.

APA, Harvard, Vancouver, ISO, and other styles

6

Kwa, Kelvin Sian Kiat. "Characterisation of strained silicon / silicon germanium metal-oxide-semiconductor devices." Thesis, University of Newcastle Upon Tyne, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405358.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Wu, Kehuey. "Strain effects on the valence band of silicon piezoresistance in p-type silicon and mobility enhancement in strained silicon pMOSFET /." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0008390.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Bowes, Sarah-Jane. "The study of Si-O bonds in low temperature matrices and in the gas phase." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342658.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Bae, Dohyun. "Sputtering fabrication of silicon nitride and silicon oxide based dichroic mirrors." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98645.

Full text

Abstract:

Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 37).
Thin films in optical materials utilize the properties of multiple materials to obtain specific and fine-tuned transmission, absorption and reflectance at wavelengths. Dichroic mirrors exhibit very different reflectance and transmission rates at certain cut-off wavelengths, which can be adjusted using changes in layer materials and thickness. This is due to constructive optical interference between alternating layers of two thin films of different refractive indices. This study explored the sputtering methods of thin-film multilayers to form dichroic mirrors in the visible spectrum for future solar-cell applications. Silicon oxide and silicon nitride targets were selected as materials used in the sputtering process. The sputtered multilayers and films were then characterized and analyzed using spectrophotometry. The transmission spectrum of the initial multilayer depicted failure in transmission at wavelengths under 500nm. The components of the multilayer were then sputtered and analyzed to troubleshoot the problematic nitride films. Transmission spectra were utilized to select each following process, and both reactive sputtering and cosputtering were explored as means of creating nitride films with functional properties. Transmission spectra were analyzed using the Swanepoel method to quantify optical characteristics to assure reactive sputtering of the targets in a nitrogen environment as a viable direction of mirror construction. Possible further work include the use of other targets such as titanium oxide, and different chamber gas mixtures for finer control in the composition of the film layers.
by Dohyun Bae.
S.B.

APA, Harvard, Vancouver, ISO, and other styles

10

Moskowitz, Steven. "Atomic force miscroscopy [sic] study of SiO₂/Si(111)--(7x7) grown via atomic oxygen plasma /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/11556.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Owen, Michael Paul. "Electron tunnelling in metal-oxide-silicon structures." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386759.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Dragosavac, Marko. "Electron transport in ultrathin oxide silicon MOSFETs." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614808.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Hung, Kwok-kwong. "Electrical characterization of Si-SiO2 interface for thin oxides /." [Hong Kong : University of Hong Kong], 1987. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12232580.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Robertson, P. A. "The photo-enhanced deposition of amorphous silicon and silicon oxide thin films." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384563.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Liu, Zhihong. "A study of thermally nitrided silicon dioxide thin films for metal-oxide-silicon VLSI techology /." [Hong Kong : University of Hong Kong], 1990. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12718488.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Kim, Dong-Geun. "Experimental study and thermodynamic modelling of the calcium oxide - silicon oxide - aluminum oxide - calcium fluoride system." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106562.

Full text

Abstract:

Mould flux for the continuous casting process is a major concern for the steelmaking industry. Nowadays, more than 90 % of steel is being produced by the continuous casting process, which requires mould flux as an essential additive. The development of mould flux has been achieved by the conventional trial and error approach since it was first introduced in industry in the 1960s. Recently, the interest on the properties of fluorine has increased a lot since it is reported that fluorine has important functions such as playing a critical role on the crystallization behavior, and decreasing the melting point and viscosity of slag. However, the conventional way to find a suitable mould flux is not efficient to face the increasingly stringent requirements of the continuous casting process such as thin slab casting and higher casting speed. Therefore, fundamental phase diagram study on mould flux systems is clearly necessary, and thermodynamic modeling is the most effective way to design new mould flux in terms of time and money saving. The major components of mould flux, the CaO-SiO2-Al2O3-CaF2 system, are investigated in this study as these four constituents will mostly affect the largest numbers of properties. Unfortunately, fluorine has high volatility at high temperature and high reactivity with other materials. Therefore, the results of previous experiments on F-containing systems are characterized by large discrepancies due to composition alteration and unexpected reactions during the experiment. As literature data show inconsistent results between each other, key phase diagram experiments were performed in this study. The phase diagram experiments were conducted with the quenching method in sealed Pt capsules to prevent fluorine loss during the experiment. The analyses were performed using a FE-SEM equipped with an EDS system, and a newly developed technique which produces more precise quantitative results for the equilibrium phase composition. The CaO liquidus of the CaO-CaF2 binary system, which the literature data differ from each other by up to 50 mol %, was confirmed. The CaO solubility in solid CaF2 was found for the first time and reaches about 5 mol % at the eutectic temperature. The liquidus of the CaO-Al2O3-CaF2 and CaO-SiO2-CaF2 systems were carefully studied and the miscibility gap in the CaO-Al2O3-CaF2 system was proved to be much smaller than that reported in literature. Also, thermal analysis was performed using DSC in a Pt crucible. The eutectic temperatures of the CaO-CaF2 and CaAl2O4-CaF2 systems were successfully measured and the α to β-CaF2 polymorphic transition was confirmed. Based on the new experimental data and reliable literature data, thermodynamic modeling of the CaO-SiO2-Al2O3-CaF2 system was also carried out. The results of thermodynamic calculation can be very beneficial for new mould flux design.
L'usage des poudres de coulée continue est une préoccupation majeure pour l'industrie sidérurgique. Actuellement, plus de 90% de l'acier est produit par le procédé de coulée continue, nécessitant impérativement l'emploi de poudres de coulée. Traditionnellement, le développement des poudres de coulée a été réalisé par la méthode d'essai et d'erreur depuis son introduction dans l'industrie dans les années 1960. Récemment, l'intérêt porté sur le fluor s'est accru car celui-ci présente d'importantes propriétés et fonctions pour le procédé de coulée continue, telles que son influence sur la cristallisation et la diminution du point de fusion et de la viscosité du laitier. Toutefois, la méthode conventionnelle de développement des poudres de coulée appropriées n'est pas efficace pour faire face aux exigences croissantes du procédé de coulée continue, telles qu'effectuer la coulée de brames minces et atteindre de plus grande vitesse de coulée. Par conséquent, l'étude fondamentale du diagramme de phase des systèmes de poudres de coulée est manifestement nécessaire, et la modélisation thermodynamique est le moyen le plus efficace pour concevoir de nouvelles poudres de coulée en termes d'économie de temps et d'argent. Les principaux composants des poudres de coulée, qui font partie du système CaO-SiO2-Al2O3-CaF2, sont examinés dans cette étude car ces quatre constituants affecteront le plus grand nombre de propriétés des poudres de coulée. Malheureusement, le fluor a une volatilité élevée à haute température et une réactivité élevée avec d'autres matériaux. Par conséquent, les résultats des expériences effectuées précédemment sur les systèmes contenant des fluorures sont caractérisés par des écarts importants en raison du changement de composition et de réactions inattendues lors des expériences. Comme les données disponibles dans la littérature rapportent des résultats contradictoires entre eux, des expériences ont été effectuées dans cette étude pour établir les diagrammes de phase. Ces expériences ont été menées avec la méthode de trempe dans des capsules de platine scellées pour empêcher la perte de fluor pendant les expériences. Les analyses ont été effectuées en utilisant un microscope électronique à balayage (MEB) équipé d'un système d'analyse dispersive en énergie de rayons X (EDS), et une technique nouvellement développée qui produit des résultats plus précis lors de la quantification de la composition des phases à l'équilibre. La courbe du liquidus du CaO du système binaire CaO-CaF2, dont les données dans la littérature diffèrent entre elles jusqu'à environ 50 % atomique, a été confirmée. La solubilité de CaO dans CaF2 à l'état solide a été trouvée pour la première fois et atteint environ 5 % atomique à la température eutectique. Les courbes de liquidus des systèmes CaO-Al2O3-CaF2 et CaO-SiO2-CaF2 ont été soigneusement étudiées et l'étendue de la lacune de miscibilité dans le système CaO-Al2O3-CaF2 a été prouvée être beaucoup plus petite que celle rapportée dans la littérature. En outre, une analyse thermique a été réalisée par calorimétrie différentielle à balayage (DSC) dans un creuset en platine. La température eutectique des systèmes CaO-CaF2 et CaAl2O4-CaF2 a été mesurée avec succès et la transition polymorphique de la forme α-CaF2 vers la forme β-CaF2 a été confirmée. Sur base des nouvelles données expérimentales et des données fiables de la littérature, la modélisation thermodynamique du système CaO-SiO2-Al2O3-CaF2 a également été réalisée. Les résultats de calcul thermodynamique peuvent être très bénéfiques pour la conception de nouvelles poudres de coulée.

APA, Harvard, Vancouver, ISO, and other styles

17

Olsen, Sarah H. "Strained silicon/silicon germanium heterojunction n-chanel metal oxide semiconductor field effect transistors." Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246619.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Ali, Danish. "Coulomb blockade in silicon-on-insulator." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321368.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Shih, Jeanne-Louise. "Zinc oxide-silicon heterojunction solar cells by sputtering." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112583.

Full text

Abstract:

Heterojunctions of n-ZnO/p-Si solar cells were fabricated by RF sputtering ZnO:Al onto boron-doped (100) silicon (Si) substrates. Zinc Oxide (ZnO) films were also deposited onto soda lime glass for electrical measurements. Sheet resistance measurements were performed with a four-point-probe on the glass samples. Values for samples evacuated for 14 hours prior to deposition increased from 7.9 to 10.17 and 11.5 O/□ for 40 W, 120 and 160 W in RF power respectively. In contrast, those evacuated for 2 hours started with a higher value of 22.5 O/□, and decreased down to 7.6 and 5.8 O/□. Vacuum annealing was performed for both the glass and the Si samples. Current-voltage measurements were performed on the ZnO/Si junctions in the dark and under illumination. Parameters such as open-circuit voltage, Voc; short-circuit current, Isc; fill factor, FF; and efficiency, eta were determined. A maximum efficiency of 0.25% among all samples was produced, with an I sc of 2.16 mA, Voc of 0.31V and a FF of 0.37. This was a sample fabricated at an RF power of 80 W. Efficiency was found to decline with vacuum annealing. Furthermore, interfacial state density calculated based on capacitance-voltage measurements showed an increase in the value with vacuum annealing. The results found suggest that the interface states may be due to an interdiffusion of atoms, possibly those of Zn into the Si surface. The Electron Beam Induced Current (EBIC) method was used to determine diffusion length to be at a value ∼40--80 mum and therefore a minority carrier lifetime calculated of 3 musec. It was also used to determine the surface recombination velocity (SRV) of the fractured surface of the Si bulk from the fabricated solar cells. An SRV of ∼500 cm/sec was determined from the fractured Si surface, at a point located at 30 and 20 mum away from the junction interface.

APA, Harvard, Vancouver, ISO, and other styles

20

Han, Lei. "IMPROVEMENT OF SILICON OXIDE QUALITY USING HEAT TREATMENT." UKnowledge, 2012. http://uknowledge.uky.edu/ece_etds/5.

Full text

Abstract:

In decades, the tremendous development of integrated circuits industry could be mostly attributed to SiO2, since its satisfactory properties as a gate dielectric candidate. The effectivity of SiO2 has been challenged since dielectric layer was scaled down below 3nm, when the gate leakage current of SiO2 became unacceptable. Institution to silicon-based CMOS techniques were proposed, but they have their own limitations. Nowadays, materials with high dielectric constants are mainstream gate dielectric materials in industry, but a SiO2 interfacial layer is still necessary to avoid gap between gate dielectric layer and Si substrate, and to minimize interface trap charges. In this thesis work, by applying lateral heating process on Si wafer with thermally grown ultrathin SiO2, the gate leakage current density could be reduced by 3-5 order of magnitude. MOS capacitors were fabricated, and electrical properties were tested with semiconductor parameter analyzer and LCR meter. The underlying mechanism of this appealing phenomenon was explored. Since unacceptable gate leakage current is one of the main reasons which prevent the scaling trend in semiconductor industry, this technology brings a possibility to post-pone the end of scaling trend, and pave a way for extensive application in industry. A new method for fabrication of MOS capacitors metal gate has been developed, and lift-off process has been replaced by wet etching process. This method provides better contact between dielectric layer and metal gate, meanwhile much easier operation.

APA, Harvard, Vancouver, ISO, and other styles

21

Chin, Miao. "Complementary metal oxide silicon cyclic redundancy check generators." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Foster, David. "Densification of silicon carbide with mixed oxide additives." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295478.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Jun, Kimin. "Iron-oxide catalyzed silicon photoanode for water splitting." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69240.

Full text

Abstract:

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 130-139).
This thesis presents an integrated study of high efficiency photoanodes for water splitting using silicon and iron-oxide. The fundamental limitations of silicon to water splitting applications were overcome by an ultrathin iron-oxide film stack and a pH-adjusted electrochemical environment. It was experimentally demonstrated that this functional photoanode has very strong photoactivity exceeding the performance of previously reported systems. A complete theoretical explanation is provided with experimental substantiations. Two major obstacles of the application of silicon to water splitting are its high valence band edge and the lack of catalytic functionality. The solution for band edge mismatch is to facilitate the unique pH response of silicon with respect to electrolyte pH. As opposed to the low pH, a high pH electrolyte allows the silicon valence band edge to be located below the oxygen evolution potential, providing physical platform for the water oxidation reaction. In this platform, the introduction of a thin iron-oxide layer was proved to effectively catalyze the anode reaction which is otherwise impossible. The very thin film enables the separation of the two key functions of the photoelectrode: photocarrier generation and catalysis. Since the iron-oxide film has a very low absorption of incident light, phorocarriers are generated in the silicon layer, while the surface still maintains catalytic functionality. By this functional separation, it was possible to overcome the loss incurred by poor electronic and photovoltaic properties of iron-oxide. The thin semiconducting film also allows a space charge region to span beyond the catalyst layer to silicon, inducing a large built-in potential to lower the required overpotential. Additional improvement was made by adopting silicon microfabrication techniques to maximize light harvesting and minimize potential losses in silicon layer. By vertical wires and ohmic contact formation, the onset potentials were decreased and the current-potential slopes were steepened, resulting in current density as high as 17 mA/cm² at zero overpotential. These results were obtained with two of the most abundant materials, and as such shows the prospect of an efficient solar-driven water splitting pathway. In addition, the comprehensive theoretical explanations will contribute to searching for further system improvements.
by Kimin Jun.
Ph.D.

APA, Harvard, Vancouver, ISO, and other styles

24

Lopez, Mark Gerard. "Aspects of electroforming in silicon oxide thin films." Thesis, Keele University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385191.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Jensen, Sophia, Leonardo Montillo, and Yogesh Periwal. "Silicon Rich Oxide UV Sensor: A Feasibility Study." The University of Arizona, 2009. http://hdl.handle.net/10150/623979.

Full text

Abstract:

Class of 2009 Abstract
OBJECTIVES: The purpose of the project was to identify two technologies from INAOE, Instituto Nacional de Astrofisica Optica y Electronica (INAOE) located in Puebla, Mexico, that were close to market and develop a feasibility study for those technologies in a 10 week time frame. METHODS: Open submission from INAOE researchers was allowed for two weeks. Following open submission a weighted criteria matrix was developed to identify the top eight technologies. Interviews were conducted with the top eight primary researchers and their laboratories over a one week period. Voting was conducted to determine the final two technologies. Research was conducted to analyze and identify the market, provide a business and financial model, and provide recommendations. RESULTS: Results are from the feasibility study of the silicon rich oxide UV sensor one of the two technologies selected. Market: Five markets were identified with combined annual production of approximately 3.5 million sensors per year and an annual expected growth rate of 9.1%. Average selling price of a commercially available UV sensor was approximately $35 per unit. Average selling price for the INOAE was estimated to be $18 per unit. Financial: A financial analysis for a start-up venture to sell and manufacture the sensor estimated gross sales in year 1 to be $2.7M, with a net profit $427K, and EBITDA $719K. The target market share of 2%, effective tax rate 40%, market risk premium 10%, discount rate (Wacc) 20.1%, and no debt was used. Start-up costs included a net investment of $279K. A licensing model $150K with 3% royalty fees from revenue was also considered. CONCLUSIONS: Research and information uncovered in the feasibility study supported a move to patent and license the UV sensor technology and move away from creating a new start-up. A thorough market analysis coupled with a conservative financial analysis allowed for the final decision. Five months from the start of the project, a licensing agreement was signed by INOAE and Impulsora Tack for a deal worth $500K, the first licensing agreement ever for the institute. Another first were patents for the technology, never before were any technologies patented by INOAE since its foundation in 1971. This project was made possible by a grant from the Brown Foundation.

APA, Harvard, Vancouver, ISO, and other styles

26

Carroli, Marco. "Silicon oxide nitride (sion) films per applicazioni fotovoltaiche." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6165/.

Full text

Abstract:

La ricerca, negli ultimi anni, si è concentrata sullo studio di materiali con energy gap più ampio del silicio amorfo a-Si per ridurre gli assorbimenti parassiti all'interno di celle fotovoltaiche ad eterogiunzione. In questo ambito, presso l'Università di Costanza, sono stati depositati layers di silicon oxynitride amorfo a-SiOxNy. Le promettenti aspettative di questo materiale legate all'elevato optical gap, superiore ai 2.0 eV, sono tuttavia ridimensionate dai problemi intrinseci alla struttura amorfa. Infatti la presenza di una grande quantit a di difetti limita fortemente la conducibilita e aumenta gli effetti di degradazione legati alla luce. In quest'ottica, nella presente tesi, sono stati riportati i risultati di analisi spettroscopiche eseguite presso il Dipartimento di Fisica e Astronomia di Bologna su campioni di silicon oxynitride nanocristallino nc-SiOxNy, analisi che hanno lo scopo di osservare come la struttura nanocristallina influisca sulle principali proprieta ottiche e sulla loro dipendenza da alcuni parametri di deposizione.

APA, Harvard, Vancouver, ISO, and other styles

27

Zhan, Nian. "Fabrication and characterization of hafnium oxide films prepared by direct sputtering /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202003%20ZHAN.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Song, Dengyuan Centre for Photovoltaic Engineering UNSW. "Zinc oxide TCOs (Transparent Conductive Oxides) and polycrystalline silicon thin-films for photovoltaic applications." Awarded by:University of New South Wales. Centre for Photovoltaic Engineering, 2005. http://handle.unsw.edu.au/1959.4/29371.

Full text

Abstract:

Transparent conductive oxides (TCOs) and polycrystalline silicon (poly-Si) thin-films are very promising for application in photovoltaics. It is extremely challenging to develop cheap TCOs and poly-Si films to make photovoltaic devices. The aim of this thesis is to study sputtered aluminum-doped ZnO TCO and poly-Si films by solid-phase crystallization (SPC) for application in low-cost photovoltaics. The investigated aspects have been (i) to develop and characterize sputtered aluminum-doped ZnO (ZnO:Al) films that can be used as a TCO material on crystalline silicon solar cells, (ii) to explore the potential of the developed ZnO:Al films for application in ZnO:Al/c-Si heterojunction solar cells, (iii) to make and characterize poly-Si thin-films on different kinds of glass substrates by SPC using electron-beam evaporated amorphous silicon (a-Si) [referred to as EVA poly-Si material (SPC of evaporated a-Si)], and (iv) to fabricate EVA poly-Si thin-film solar cells on glass and improve the energy conversion efficiency of these cells by post-crystallization treatments. The ZnO:Al work in this thesis is focused on the correlation between film characteristics and deposition parameters, such as rf sputter power (Prf), working gas pressure (Pw), and substrate temperature (Tsub), to get a clear picture of film properties in the optimized conditions for application in photovoltaic devices. Especially the laterally non-uniform film properties resulting from the laterally inhomogeneous erosion of the target material are investigated in detail. The influence of Prf, Pw and Tsub on the structural, electrical, optical and surface morphology properties of ZnO:Al films is discussed. It is found that the lateral variations of the parameters of ZnO:Al films prepared by rf magnetron sputtering can be reduced to acceptable levels by optimising the deposition parameters. ZnO:Al/c-Si heterojunction solar cells are fabricated and characterized to demonstrate the feasibility of the fabricated ZnO:Al films for application in heterojunction solar cells. In this application, expensive indium-tin oxide (ITO) is usually used. Under the standard AM1.5G spectrum (100 mW/cm2, 25 ??C), the best fabricated cell shows an open-circuit voltage of 411 mV, a short-circuit current density of 30.0 mA/cm2, a fill factor of 66.7 %, and a conversion efficiency of 8.2 %. This is believed to be the highest stable efficiency ever reported for this type of cell. By means of dark forward current density-voltage-temperature (J-V-T) measurements, it is shown that the dominant current transport mechanism in the ZnO:Al/c-Si solar cells, in the intermediate forward bias voltage region, is trap-assisted multistep tunneling. EVA poly-Si thin-films are prepared on four types of glass substrates (planar and textured glass, both either bare or SiN-coated) based on evaporated Si, which is a cheaper Si deposition method than the existing technologies. The textured glass is realized by the UNSW-developed AIT process (AIT = aluminium-induced texture). The investigation is concentrated on finding optimized process parameters and evaluating film crystallization quality. It is found that EVA poly-Si films have a grain size in the range 0.8-1.5 ??m, and a preferential (111) orientation. UV reflectance and Raman spectroscopy measurements reveal a high crystalline material quality, both at the air-side surface and in the bulk. EVA cells are fabricated in both substrate and superstrate configuration. Special attention is paid to improving the Voc of the solar cells. For this purpose, after the SPC process, the samples receive the two post-crystallization treatments: (i) a rapid thermal anneal (RTA), and (ii) a plasma hydrogenation. It is found that two post-crystallization treatments more than double the 1-Sun Voc of the substrate-type cells. It is demonstrated that RTA improves the structural material quality of the cells. Furthermore, a hydrogenation step is shown to significantly improve the electronic material quality of the cells. Based on the RTA???d and hydrogenated EVA poly-Si material, the first mesa-type EVA cells are fabricated in substrate configuration, by using sputtered Al-doped ZnO as the transparent front contact. The investigation is focused on addressing the correlation between the type of the substrate and cell performance. Optical, electrical and photovoltaic properties of the devices are characterized. It is found that the performance of EVA cells depends on the glass substrate topography. For cells on textured glass, the AIT texture is shown to have a beneficial effect on the optical absorption of EVA films. It is demonstrated that a SiN barrier layer on the AIT-textured glass improves significantly both the crystalline quality of the poly-Si films and the energy conversion efficiency of the resulting solar cells. For cells on planar glass, a SiN film between the planar glass and the poly-Si film has no obvious effect on the cell properties. The investigations in this thesis clearly show that EVA poly-Si films are very promising for poly-Si thin-film solar cells on glass.

APA, Harvard, Vancouver, ISO, and other styles

29

劉志宏 and Zhihong Liu. "A study of thermally nitrided silicon dioxide thin films for metal-oxide-silicon VLSI techology." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1990. http://hub.hku.hk/bib/B31231895.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Al-Ahmadi, Ahmad Aziz. "COMPLEMENTARY ORTHOGONAL STACKED METAL OXIDE SEMICONDUCTOR: A NOVEL NANOSCALE COMPLEMENTRAY METAL OXIDE SEMICONDUCTOR ARCHTECTURE." Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1147134449.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Özdağ, Pınar Güneş Mehmet. "Capacitance-voltage spectroscopy in metal-tantalum pentoxide (Ta-O)-silicon mos capacitors/." [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/fizik/T000397.pdf.

Full text

Abstract:

Thesis (Master)--İzmir Institute of Technology, İzmir, 2005
Keywords: Capacitance-voltage spectroscopy, high dielectric constant insulators, tantalum pentoxide. Includes bibliographical references (leaves 92-97)

APA, Harvard, Vancouver, ISO, and other styles

32

Sun, Shan. "Power metal-oxide-semiconductor field-effect transistor with strained silicon and silicon germanium channel." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4631.

Full text

Abstract:

With the development of modern electronics, the demand for high quality power supplies has become more urgent than ever. For power MOSFETs, maintaining the trend of reducing on-state resistance (conduction loss) without sacrificing switching performance is a severe challenge. In this work, our research is focused on implementing strained silicon and silicon germanium in power MOFETs to enhance carrier mobility, thus achieving the goal of reducing specific on-state resistance. We propose an N-channel super-lattice trench MOSFET, a P-channel sidewall channel trench MOSFET and P-Channel LDMOS with strained Si/SiGe channels. A set of fabrication processes highly compatible with conventional Si technology is developed to fabricate proposed devices. The mobility enhancement is observed to be 20%, 40% and 35% respectively for N-channel, P-channel trench MOSFET and LDMOS respectively and the on-state resistance is reduced by 10%, 20% and 22% without sacrificing other device performance parameters.
ID: 030423174; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2010.; Includes bibliographical references (p. 85-91).
Ph.D.
Doctorate
Department of Electrical Engineering
Engineering and Computer Science

APA, Harvard, Vancouver, ISO, and other styles

33

Richter, Alexei [Verfasser], Uwe [Akademischer Betreuer] Rau, and Joachim [Akademischer Betreuer] Knoch. "Nanocrystalline silicon oxide in silicon heterojunction solar cells / Alexei Richter ; Uwe Rau, Joachim Knoch." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://nbn-resolving.de/urn:nbn:de:101:1-2019051406005972709643.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Richter, Alexei Verfasser], Uwe [Akademischer Betreuer] [Rau, and Joachim [Akademischer Betreuer] Knoch. "Nanocrystalline silicon oxide in silicon heterojunction solar cells / Alexei Richter ; Uwe Rau, Joachim Knoch." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069112/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

洪國光 and Kwok-kwong Hung. "Electrical characterization of Si-SiO2 interface for thin oxides." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B31230866.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Jan, Ying-Wei. "A switched-capacitor analysis metal-oxide-silicon circuit simulator." Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1181163717.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Thornton, John M. C. "Some aspects of silicon surface modification and oxide removal." Thesis, Cardiff University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314790.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Magden, Emir Salih. "Rare-earth doped aluminum oxide lasers for silicon photonics." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/89860.

Full text

Abstract:

Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
88
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 61-66).
A reliable and CMOS-compatible deposition process for amorphous Al2O3 based active photonic components has been developed. Al2O3 films were reactively sputtered, where process optimization was achieved at a temperature of 250°C, with a deposition rate of 8.5 nm/min. With a surface roughness of 0.3 nm over a 1 [mu]m2 area, background optical losses as low as 0.1 dB/cm were obtained for undoped films. The development of active photonics components has been realized by use of rare-earth metals as dopants. By co-sputtering aluminum and erbium targets, Er3+ dopants at concentrations on the order of 1.0x1020 cm-3 have been added to the Al2O3 host medium. Resulting Er3+:Al2O3 films have been characterized, and over 3 dB/cm absorption has been measured over a 20 nm bandwidth. Following the material development, distributed Bragg reflector lasers were designed and fabricated in a CMOS foundry. The laser cavity was created by introducing gratings on either side of a Si3N4 waveguide. Er3+:Al2O3 was deposited in SiO2 trenches on top of the Si3N4 layer, eliminating the need for any subsequent etching steps. On-chip laser output of 3.9 [mu]W has been recorded at a wavelength of 1533.4 nm, with a side mode suppression ratio over 38.9 dB.
by Emir Salih Magden.
S.M.

APA, Harvard, Vancouver, ISO, and other styles

39

Lee, Grace W. (Grace Wang). "Optical absorption of bismuth silicon oxide (Bi₁₂SiO₂₀) crystals." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/114089.

Full text

Abstract:

Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 23).
The purpose of this work is to characterize the optical absorption in bismuth silicon oxide (Bi₁₂SiO₂₀) crystals grown using the Bridgman technique and to identify electronic transitions responsible for absorption. Optical measurements were taken in the range of 0.4 - 11 pm at 300 K and 77 K using a spectrometer. The results show that near the band edge, there is evidence of indirect transitions at 2.3 eV and excition transitions at 1.8 eV. Low temperature measurements revealed peaks of free carrier absorption in the visible light range at 1.7 eV and 2.1 eV. Illuminated samples at low temperature revealed empty donor levels in the visible range at 1.6-1.9 eV and 2.1 eV, indicating the presence of the photochromic effect and photorefractivity.
by Grace W. Lee.
S.B.

APA, Harvard, Vancouver, ISO, and other styles

40

Mather, Sean. "Hafnium oxide based gate stacks on germanium and silicon." Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3007146/.

Full text

Abstract:

Up until 2007 the heart of the metal-oxide-semiconductor-field-effect-transistor (MOSFET) in computer processors was based on the Si-SiO2-poly Si system. This changed when Intel announced the fabrication of the high-k metal gate MOSFET. This was required because the SiO2 layer had become too thin so that quantum mechanical tunnelling meant that the leakage current through the device was unacceptably high. As the high quality SiO2 layer was the main reason for silicon it is now possible for a semiconductor with better electrical properties to be used. The International Technology Roadmap for Semiconductors (ITRS) states that this is due to happen in 2018. Germanium is one of the contending materials due to high carrier mobilities (2x electron and 4x hole enhancement over silicon). This thesis studies the development of high-k dielectrics deposited by atomic layer deposition (ALD), specifically the dielectric constant enhancement of HfO2 with the addition of titanium. Different preparation methods were then deployed to create Hafnium based gate stacks on germanium. These methodologies are divided into 4 sections. Firstly, to grow a germanium oxide layer by oxygen plasma with the subsequent deposition of high-k on top. Then Molecular Beam Epitaxy (MBE) of an ultra-thin aluminium layer to create an ultra-thin gate stack with high-k deposited on top to reduce the leakage current through the devices. Then ALD of a thin Al2O3 layer with high-k on top and finishes with sulphur passivation of the Ge interface with high-k on top. These material systems were characterised by both physical (ellipsometry, X-ray diffraction, X-ray photoelectron spectroscopy, Transmission electron microscopy) and electrical (Capacitance-voltage, Current-voltage) means. The dielectric constant of HfO2 was found to increase from 17 to 35 for the Ti0.5Hf0.5O2 system. This then reduced upon annealing to 27 with a 30 minute N2 anneal at 500°C and 22 with a 30s spike anneal at 850oC.Growing a germanium oxide layer by oxygen plasma gave reasonable C-V characteristics but the thickness of the layer at 3nm was too large to make it suitable for extremely scaled devices. By giving the germanium a thermal clean in the MBE chamber and depositing an ultra-thin Aluminium layer which was subsequently oxidised a structure with an equivalent oxide thickness of 1.3nm were achieved with low leakage currents of 2x10-4Acm-2 and low hysteresis of 10mV. The leakage current dropped to 3x10-7Acm-2 for a sample with an EOT of 1.5nm. The equivalent oxide thickness (EOT) was found to be related to the temperature of the thermal preclean with higher temperatures giving lower EOT's due to a more efficient removal of the native oxide. EOT was also found to reduce for samples after a forming gas anneal which is attributed to densification of the layers and a reduction of the GeOx interfacial layer. ALD of a thin Al2O3 layer and subsequent plasma ALD of HfO2 showed that significant regrowth of GeOx occurs even when 2nm thick Al2O3 barrier is employed. The electrical data is similar to samples without the Al2O3 layer which could be due to it not being thick enough to suppress an unwanted interfacial layer forming. Sulphur passivation gave very good C-V data when Al2O3 is used as a dielectric and conduction band offsets were calculated as being 3.3eV for S-passivated samples and 3.61eV without S-passivation. Both of these are well over the 1eV set out by the ITRS to reduce carrier injection from the channel through the device. Device performance was found to be not as good when HfO2 was used as the dielectric as there is significant regrowth of the GeOx interfacial layer. These studies show that there are a number of possible routes available for forming a gate stack on germanium and the control of the interface is the critical performance factor that needs to be controlled.

APA, Harvard, Vancouver, ISO, and other styles

41

González, Zalba Miguel Fernando. "Single donor detection in silicon nanostructures." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608181.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Tahhan, Abdulla. "Energy performance enhancement of crystalline silicon solar cells." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/14503.

Full text

Abstract:

The work in this thesis examines the effects of the application of oxide coatings on the performance of the single crystalline silicon photovoltaic solar cells. A variety of potential oxide materials for solar cells performance enhancement are investigated. These films are silicon oxide, titanium oxide and rare earth ion-doped gadolinium oxysulfide phosphor. This study compares the electrical characteristics, optical properties and surface chemical composition of mono-crystalline silicon cells before and after coating. The first study investigates the potential for using single and double layers of silicon oxide films produced by low-temperature Plasma Enhanced Chemical Vapour Deposition (PECVD) using tetramethylsilane as a silicon precursor and potassium permanganate oxidising agent for efficiency enhancement of solar cells at low manufacturing cost. Deposition of the films contributes to the increase of the conversion energy of the solar cells on one hand while the variety of colours obtained in this study can be of great importance for building-integrated photovoltaic application on the other hand. The obtained results demonstrated a relative enhancement of 3% in the conversion efficiency of the crystalline silicon solar cell. In the second study, the effects of using a single layer of titanium oxide and a stack of silicon oxide and titanium oxide on the performance of solar cell are demonstrated. Moreover, this study shows the use of different sputtering configurations and oxidation methods. The experimental results showed a relative enhancement of 1.6% for solar cells coated with a stack of silicon oxide/titanium oxide. In the third study, silicon cells were coated with a luminescent layer consisting of down-converting phosphor, gadolinium oxysulfide doped with erbium and terbium, and a polymeric binder of EVA using doctor-blade screen printing technique. A relative enhancement of 4.45% in the energy conversion efficiency of PV solar cell was achieved. Also, the effects of combining silicon oxide layers together with the luminescent composite are also presented in this study.

APA, Harvard, Vancouver, ISO, and other styles

43

Chinchani, Rameshwari. "Strained silicon/silicon-germanium heterostructure complimentary metal oxide semiconductor devices a simulation study of linearity /." Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1176143999.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Humad, Shweta. "Piezo-on-Silicon Microelectromechanical Resonators." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5069.

Full text

Abstract:

This thesis reports on the use of sputter-deposited zinc-oxide as a transduction mechanism to actuate and sense single crystal silicon (SCS) microelectromechanical (MEMS) resonators. Low frequency prototypes of piezo-on-silicon resonators with operating frequencies in the range of hundreds of kHz were implemented using micromechanical single crystal silicon clamped-clamped beam resonators. The resonators reported here extend the frequency of this technology into very high frequency (VHF range) by using in-plane length extensional bulk resonant modes. This thesis outlines the design, implementation and characterization of high-frequency single crystal silicon (SCS) block resonators with piezoelectric electromechanical transducers. The resonators are fabricated on 4m thick SOI substrates and use sputtered ZnO as the piezo material. The centrally supported block resonators operate in their first and higher order length extensional bulk modes with high quality factor (Q). Measurement results are in good agreement with the developed ANSYS simulations.

APA, Harvard, Vancouver, ISO, and other styles

45

Kang, Laeugu. "Study of HFO₂ as a future gate dielectric and implementation of polysilicon electrodes for HFO₂ films /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004301.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Akhtaruzzaman, Md. "Dielectric studies of some oxide materials, nitride ceramics and glasses." Thesis, Durham University, 1989. http://etheses.dur.ac.uk/6308/.

Full text

Abstract:

This thesis is primarily concerned with the evaluation and comparison of the dielectric behaviour of materials which may find application as substrates in microelectronic high-performance packaging. In the introductory chapter the factors governing the choice of the most suitable dielectric substrate for compatibility with silicon technology are reviewed; it is shown that in addition to good dielectric properties the thermal conductivity is important if high power packages are required together with the ability to obtain good matching of thermal expansion coefficients. This is followed by a survey of the present theories of dielectric behaviour with special emphasis on the Universal law of dielectric response and its applicability to oxide and glass ceramics which exhibit hopping conductivity. The experimental methods for the measurement of dielectric parameters are outlined in Chapter 3 which includes an account of techniques developed for studying materials only available as powders. The three substrate systems studied were aluminium oxide, aluminium nitride and glass-on-molybdenum and in the case of the two former materials a range of both pure and impure specimens were examined both in single crystal and sintered polycrystalline form. The detailed experimental results are presented and discussed in the three succeeding chapters for each of the materials in turn; these results include the values of permittivity and dielectric loss, measured over a frequency range of 5 x 10(^2) Hz to 1 x 10(^7) Hz, the temperature variation of permittivity both in the low temperature (85K to 293k) and high temperature (20ºC to about 600ºC) regions and the d.c. and a.c. conductivity in the high temperature range. In their pure form each of these materials would be suitable as a substrate, having permittivities at room temperature of ϵ ' (_s) = 10.2 for polycrystalline Al(_2)(^0)(_3), ϵ' (_s) = 9.2 for polycrystalline AlN (which has a thermal conductivity of about one-hundred times that of alumina) and ϵ' (_s) - 6.5 for glass-on-molybdenum and dielectric losses in the region of tan δ - 10(^-3). The effect of impurities is shown to be very significant leading in all cases to some increase in permittivity and a much larger increase in dielectric loss. The measurements made on powders are given and discussed in Chapter 7. In the studies on the powders used as starting materials for the manufacture of substrates it was shown that by making measurements at low temperature (77K) the effects of intergranular space charge polarization could be overcome yielding information valuable for quality control of impurity content; measurements made on powders of some high temperature oxide superconducting materials are also given. The final chapter, Chapter 8, summarises the overall conclusions of the research and makes some suggestions for future work.

APA, Harvard, Vancouver, ISO, and other styles

47

LoStracco, Gregory 1960. "Furance and carbon dioxide laser densification of sol-gel derived silicon oxide-titanium oxide-aluminum oxide planar optical waveguides." Thesis, The University of Arizona, 1994. http://hdl.handle.net/10150/291388.

Full text

Abstract:

An experimental investigation on the furnace and CO₂ laser densification of sol-gel derived SiO₂-TiO₂-Al₂O₃ planar optical waveguides was performed. Solutions containing equal mole fractions of tetraethoxysiline [Si(C₂H₅O)₄], titanium ethoxide [Ti(C₂H₅O)₄], aluminum tri-sec-butoxide [Al(C₄H₉O)₃] were used to spin films with a nominal 2:2:1 molar SiO₂-TiO₂-Al₂O₃ composition. Emphasis was placed on determining what effects the densification techniques had on film shrinkage, index change, crystallization and composition. Film shrinkage and refractive index change were found to be similar for both densification techniques. Fully dense, amorphous film were obtained with both methods. After densification, further heating caused titania crystalline phases to form with both processing techniques. However, anatase formed in the furnace fired films while rutile formed in the laser irradiated films.

APA, Harvard, Vancouver, ISO, and other styles

48

Bernard, Sheldon Ainsworth. "Influence of silicon dioxide, magnesium oxide and zinc oxide on resorbable tricalcium phosphate based bioceramics." Online access for everyone, 2005. http://www.dissertations.wsu.edu/Thesis/Fall2005/s%5Fbernard%5F083005.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Kang, Jingxuan. "Poly Silicon on Oxide Contact Silicon Solar Cells." Thesis, 2019. http://hdl.handle.net/10754/652926.

Full text

Abstract:

Silicon photovoltaic (PV) is a promising solution for energy shortage and environmental pollution. We are experiencing an era when PV is exponentially increasing. Global cumulative installation had reached 380 GW in 2017. Among which, silicon-based PV productions share more than 90% market. Performance of the first two-generation commercial popular silicon solar cells - Al-BSF and PERC - are limited by metal/Si contacts, where interface defects significantly reduce the open-circuit voltage. In this context, full-area passivation concepts are proposed for c-Si solar cells, with expectation to enhance the efficiency via reducing carrier recombination loss at the contact regions. In this thesis, poly silicon on oxide (POLO) passivating contact is developed for high efficiency c-Si solar cells. We unveiled the working mechanisms of POLO cells and then optimized the device performance based on our conclusion. We use boiling nitric acid to oxidize c-Si surface, which is of significance to determine the POLO working mechanisms. Phosphorus and boron doped silicon films are deposited by plasma enhanced vapor deposition (PECVD) or low-pressure vapor deposition (LPCVD) followed by high temperature (>800°C) annealing. SiOx structural evolution process under different annealing temperature was observed and the corresponding effects on passivation have been elucidated. The carrier transport mechanisms in the POLO contact annealed at high temperature, e.g. 800°C  900°C, were explored. We unveil that carrier transport in POLO structure is a combination of tunneling and pinhole transport, but dominant at varied temperature regions. Phosphorus-doped n-type POLO contact is optimized by several parameters, such as doping concentration, film thickness, annealing temperature, film deposition temperature, film relaxation time during annealing process, etc. We successfully obtained minority carrier lifetime over 10ms and contact resistivity lower than 30 mΩ·cm2. Boron-doped p-type POLO contact is also optimized by changing the doping concentration and annealing temperature. Finally, further hydrogen passivation is applied to enhance p-type POLO contact passivation, achieving an iVoc>690 mV, J0 <5 fA/cm2 and contact resistivity 1.3 mΩ·cm2. With the optimized n-type and p-type POLO contacts, an efficiency over 18% is achieved on n-type c-Si solar cells with a flat front surface.

APA, Harvard, Vancouver, ISO, and other styles

50

Chih, Cheng Wei, and 鄭惟之. "Formation of nano silicon channel with thin silicon-rich silicon oxide." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/02847038318764954812.

Full text

Abstract:

碩士
國立清華大學
材料科學工程學系
104
PECVD is used to deposit silicon-rich silicon dioxide thin film. After annealing process, it turns out to be silicon dioxide thin film containing nano-silicon channel. The experiment shows that silicon content increases when silane ratio was raised during deposited process. The average grain size of crystalline silicon is 5 nm. Nucleation phenomenon is observed inside the ultrathin silicon-rich silicon dioxide film and the interface. Furthermore, silicon nano channels through thin silicon-rich silicon dioxide are formed with sufficient anneal.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!