Angular distributions and total yields of atoms sputtered from bismuth targets by normally incident 10 keV -50 keV Ne+ and Ar+ ions have been measured both experimentally and by computer simulation. Polycrystalline Bi targets were used for experimental measurements. The sputtered atoms were collected on high purity aluminum foils under ultra-high vacuum conditions, and were subsequently analyzed using Rutherford backscattering spectroscopy. The Monte-Carlo based SRIM code was employed to simulate angular distributions of sputtered Bi atoms and total sputtering yields of Bi to compare with experiment. The measured sputtering yields were found to increase with increasing projectile energy for normally incident 10 keV - 50 keV Ne+ and Ar+ ions. The shapes of the angular distributions of sputtered Bi atoms demonstrated good agreement between experiment and simulation in the present study. The measured and simulated angular distributions of sputtered Bi exhibited an over-cosine tendency. The measured value of the degree of this over-cosine nature was observed to increase with increasing incident Ne+ ion energy, but was not strongly dependent on incident Ar+ ion energy. The differential angular sputtering yield and partial sputtering yields due to Ar ion bombardment of an inhomogeneous liquid Bi:Ga alloy have been investigated, both experimentally and by computer simulation. Normally incident 25 keV and 50 keV beams of Ar+ were used to sputter a target of 99.8 at% Ga and 0.2 at% Bi held at 40° C in ultra-high vacuum (UHV), under which conditions the alloy is known to exhibit extreme Gibbsian surface segregation that produces essentially a monolayer of Bi atop the bulk liquid. Angular distributions of sputtered neutrals and partial sputtering yields obtained from the conversion of areal densities of Bi and Ga atoms on collector foils were determined. The Monte-Carlo based SRIM code was employed to simulate the experiment and obtain the angular distribution of sputtered components. The angular distribution of sputtered Ga atoms, originating from underneath the surface monolayer, was measured to be sharply peaked in angle about the surface normal direction compared to the Bi atoms originating from surface monolayer. The simulation study produced contradicting results, where the species originating from surface monolayer was strongly peaked around the surface normal compared to the species originating from beneath the surface monolayer.

Orientador: José Humberto Dias da Silva / Coorientador: Paulo Noronha Lisboa Filho / Banca: Valmor Roberto Mastelaro / Banca: Wido Herwig Schreiner / Banca: Francisco Eduardo Contijo Guimarães / Banca: Antonio Ricardo Zanata / Resumo: A busca por um melhor entendimento da inter-relação entre os parâmetros envolvidos no processo de crescimento de filmes de dióxido de titânio (Tio2) e as propriedades estruturais, eletrônicas e magnéticas resultantes foi a principal motivação deste trabalho. Para isso, filmes Ti)2 foram crescidos usando a técnica de RF magnetron sputtering em diferentes condições. Um primeiro conjunto de filmes de Ti)2 não dopados foi depositado com fluxo contínuo de O2. Em outro conjunto, utilizou-se sistemáticas interrupções no fluxo de O2 durante a deposição. O último grupo de amostras foi depositado usando fluxo contínuo O2 e dopagem com Mn. Os filmes do primeiro grupo apresentaram morfologia colunar com estrutura majoritariamente anatase e com gap óptico de ~3,3 eV, independente da temperatura dos substratos (450ºC e 600ºC) e da razão Ar/O2 utilizada. A diminuição do fluxo de O2 provocou um aumento da absorção sub-gap que foi associada a um aumento dos defeitos eletrônicos no material. Um tratamento térmico em vácuo a 800ºC, realizado sobre filmes de TiO2 puros, revelou um aumento da fração rutila e da absorção óptica, o que também foi associado a um aumento da concentração de defeitos eletrônicos. A análise dos filmes onde o fluxo de oxigênio foi sistematicamente interrompido durante a deposição mostrou que o aumento no número de interrupções não interferiu significativamente na morfologia colunar dos filmes, mas produziu um considerável aumento na fração rutila dos filmes, bem como um aumento na absorção óptica sub-gap. O aumento na absorção na região do visível e infravermelho próximo foi atribuído a um aumento na concentração de defeitos que, de acordo com cálculos baseados na teoria do funcional da densidade, estão relacionados a estados de energia provenientes de vacâncias de oxigênio. Os filmes de TiO2 dopados com diferentes concentrações de Mn pertencentes ao terceiro grupo também / Abstract: The search for a better understanding of the interrelation between the parameters involved in the process of film growth and the resulting structural, electronic and magnetic properties was the main motivation of this work. To the purpose, TiO2 films were grown by RF magnetron sputtering technique in different conditions. In a first set, TiO2 films were deposited with continuous O2 flow. In another set, systematic interruptions in the O2 flow were performed during the deposition. The last group of samples was deposited using a continuous O2 flow and Mn doping. A detailed analysis of the first group showed that these films exhibit columnar morphology with mainly anatase structure and optical gap of ~3.3eV, independent of the substrate temperature (450ºC and 600ºC) and the ratio used. THe decrease in O2 flux caused an increase in the sug gap absorption which associated with the increase in electronic defects of the material. Anneling in vacuum at 800ºC performed on pure TiO2 films showed an increase in the rutilo fraction, a red shift of the optical absorption edge, and an increase of the sub gap absorption associated with the increase of the electronic defects. The analysis of the films were the O2 flow was systematically interrupted during the deposition showed that the increase in the number of interruptions did not interfere significantly in the columnar morphology, but produced a significant increase in the fraction of rutile and brookite as well as an increase in sub-gap absorption. The increase in absorption in the visible and near infrared was attributable to an increase in the concentration of defects that, according to calculations based on the density functional theory, should be related to energy states provides by O vacancies. The Mn doped films also present a compact columnar morphology and a strong and systematic favoring of the rutile... (Complete abstract click electronic access below) / Doutor

by Fung Chi Keung = 採用脈衝直流電源對靶濺射技術製備銦錫氧化物薄膜的硏究 / 馮志強. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Fung Chi Keung = Cai yong mai chong zhi liu dian yuan dui ba jian she ji shu zhi bei yin xi yang hua wu bo mo de yan jiu / Feng Zhiqiang. / Acknowledgements --- p.i / Abstract --- p.ii / 論文摘要 --- p.iii / Table of contents --- p.iv / List of figures --- p.viii / List of tables --- p.xii / Chapter Chapter 1 --- Introduction --- p.1-1 / Chapter 1.1 --- Genesis --- p.1-1 / Chapter 1.2 --- Aims and Objectives --- p.1-1 / Chapter 1.3 --- Layout of Thesis --- p.1-3 / References --- p.1-4 / Chapter Chapter 2 --- Literature Review --- p.2-1 / Chapter 2.1 --- Introduction to transparent conducting oxides (TCOs) --- p.2-1 / Chapter 2.2 --- Indium tin oxide (ITO) --- p.2-2 / Chapter 2.2.1 --- Use of ITO --- p.2-2 / Chapter 2.2.2 --- Structure and properties of ITO --- p.2-3 / Chapter 2.3 --- Properties of ITO films deposited by different growth techniques --- p.2-8 / Chapter 2.3.1 --- Sputtering --- p.2-9 / Chapter 2.3.2 --- Vacuum evaporation --- p.2-11 / Chapter 2.3.3 --- Spray pyrolysis --- p.2-11 / Chapter 2.3.4 --- Chemical vapor deposition (CVD) --- p.2-12 / Chapter 2.3.5 --- Reactive ion plating --- p.2-12 / Chapter 2.4 --- Contradictions in existing literature --- p.2-13 / References --- p.2-15 / Chapter Chapter 3 --- Thin Film Fabrication and Process --- p.3-1 / Chapter 3.1 --- Facing-target sputtering (FTS) --- p.3-1 / Chapter 3.2 --- Asymmetric bipolar pulsed DC power source --- p.3-3 / Chapter 3.2.1 --- Target poisoning --- p.3-3 / Chapter 3.2.2 --- Preferential sputtering --- p.3-4 / Chapter 3.2.3 --- Discussion --- p.3-4 / Chapter 3.3 --- Substrates --- p.3-6 / Chapter 3.3.1 --- Microscopic glass --- p.3-7 / Chapter 3.3.2 --- Corning 7059 glass --- p.3-8 / Chapter 3.3.3 --- Epitaxial growth --- p.3-8 / Chapter 3.3.3.1 --- Epitaxial lattice matching --- p.3-8 / Chapter 3.3.3.2 --- Yttrium stabilized zirconia (YSZ) --- p.3-9 / Chapter 3.3.3.3 --- Sapphire --- p.3-9 / Chapter 3.3.3.4 --- Silicon wafer --- p.3-11 / Chapter 3.3.4 --- Substrate cleaning --- p.3-11 / Chapter 3.4 --- Targets for the reactive sputtering of ITO films --- p.3-13 / Chapter 3.4.1 --- Indium Tin Oxide target (90wt% ln203 : 10wt% Sn04) --- p.3-14 / Chapter 3.4.2 --- Indium Tin alloy target (90wt% In : 10wt% Sn) --- p.3-14 / Chapter 3.5 --- Deposition conditions --- p.3-16 / Chapter 3.5.1 --- Sputter atmosphere --- p.3-16 / Chapter 3.5.2 --- Deposition pressure --- p.3-16 / Chapter 3.5.3 --- Deposition power --- p.3-17 / Chapter 3.5.4 --- Target to substrate distance --- p.3-17 / Chapter 3.5.5 --- Pulse frequency and pulse width --- p.3-17 / Chapter 3.6 --- Deposition --- p.3-17 / References --- p.3-19 / Chapter Chapter 4 --- Measurement and Analysis Techniques --- p.4-1 / Chapter 4.1 --- Resistivity measurement --- p.4-1 / Chapter 4.2 --- "Transmittance, reflectivity and absorption measurements" --- p.4-3 / Chapter 4.3 --- Thickness measurement --- p.4-4 / Chapter 4.4 --- "Crystal structure, surface morphology and roughness measurements" --- p.4-4 / Chapter 4.5 --- Photolithography --- p.4-7 / Chapter 4.6 --- Hall effect measurements --- p.4-8 / References --- p.4-10 / Chapter Chapter 5 --- Experimental results and discussions --- p.5-1 / Chapter 5.1 --- Effect of O2 partial pressure --- p.5-1 / Chapter 5.1.1 --- Deposition rate --- p.5-2 / Chapter 5.1.2 --- Electrical and optical properties --- p.5-4 / Chapter 5.1.3 --- Structure and orientation --- p.5-16 / Chapter 5.1.4 --- Surface morphology and roughness --- p.5-22 / Chapter 5.1.5 --- Conclusion --- p.5-29 / Chapter 5.2 --- Effect of substrate temperature --- p.5-29 / Chapter 5.2.1 --- Electrical and optical properties --- p.5-29 / Chapter 5.2.2 --- Structure and orientation --- p.5-44 / Chapter 5.2.3 --- Surface morphology and roughness --- p.5-49 / Chapter 5.2.4 --- Conclusion --- p.5-54 / Chapter 5.3 --- Effect of vacuum annealing --- p.5-54 / Chapter 5.3.1 --- Electrical and optical properties --- p.5-54 / Chapter 5.3.2 --- Conclusion --- p.5-59 / Chapter 5.4 --- Effect of different substrates --- p.5-59 / Chapter 5.4.1 --- Comparison of heteroepitaxial and polycrystalline ITO films --- p.5-60 / Chapter 5.4.2 --- Conclusion --- p.5-63 / Chapter 5.5 --- Effect of film thickness --- p.5-64 / Chapter 5.5.1 --- Film thickness calibration --- p.5-64 / Chapter 5.5.2 --- Electrical properties --- p.5-64 / Chapter 5.5.3 --- Conclusion --- p.5-67 / Chapter 5.6 --- Effect of deposition pressure --- p.5-68 / Chapter 5.6.1 --- Deposition rate --- p.5-68 / Chapter 5.6.2 --- Electrical properties --- p.5-70 / Chapter 5.6.3 --- Conclusion --- p.5-70 / Chapter 5.7 --- Effect of target pre-conditioning --- p.5-72 / Chapter 5.8 --- Conclusion --- p.5-72 / References --- p.5-74 / Chapter Chapter 6 --- Further works --- p.6-1 / Appendix I

Au Yeung Yue Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Au Yeung Yue Fung. / Abstract --- p.i / 論文摘要 --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.viii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Genesis --- p.1-1 / Chapter 1.2 --- Aims and Objectives --- p.1-2 / Chapter 1.3 --- Layout of thesis --- p.1-3 / References --- p.1-4 / Chapter Chapter 2 --- Literature review / Chapter 2.1 --- Introduction to superconductor --- p.2-1 / Chapter 2.2 --- MgB2 --- p.2-3 / Chapter 2.2.1 --- Significance of MgB2 --- p.2-3 / Chapter 2.2.2 --- Structure and properties of MgB2 --- p.2-4 / Chapter 2.2.3 --- Superconducting mechanism of MgB2 --- p.2-5 / Chapter 2.2.4 --- Physical properties of boron and boride --- p.2-7 / Chapter 2.2.5 --- Physical properties of magnesium --- p.2-7 / Chapter 2.2.6 --- Formation of MgB2 --- p.2-8 / Chapter 2.2.7 --- MgB2 thin films --- p.2-9 / Chapter 2.2.7.1 --- Substrate --- p.2-11 / Chapter 2.2.7.2 --- Substrate temperature --- p.2-12 / Chapter 2.3 --- Contradictions as revealed by existing literatures --- p.2-13 / References --- p.2-14 / Chapter Chapter 3 --- Preparation and characterization of bulk MgB2 / Chapter 3.1 --- Bulk MgB2 fabrication / Chapter 3.2 --- Measurement and analysis techniques of bulk MgB2 --- p.3-4 / Chapter 3.2.1 --- XRD --- p.3-4 / Chapter 3.2.2 --- Meissner effect measurement --- p.3-5 / Chapter 3.3 --- Sintering time of MgB2 --- p.3-6 / Chapter 3.4 --- Concentration of Mg in sintering MgB2 --- p.3-8 / Chapter 3.5 --- Sintering temperature of MgB2 --- p.3-11 / Chapter 3.6 --- Thermal stability of MgB2 --- p.3-13 / Chapter 3.7 --- MgB2 in water --- p.3-17 / References --- p.3-19 / Chapter Chapter 4 --- Preparation and characterization of MgB2thin films / Chapter 4.1 --- Thin film deposition --- p.4-1 / Chapter 4.1.1 --- Facing-target sputtering (FTS) --- p.4-2 / Chapter 4.1.2 --- Vacuum system --- p.4-4 / Chapter 4.1.3 --- Asymmetric bipolar pulsed DC power source --- p.4-6 / Chapter 4.2 --- Fabrication of MgB2 targets --- p.4-10 / Chapter 4.3 --- Substrates --- p.4-11 / Chapter 4.4 --- Deposition procedure --- p.4-12 / Chapter 4.5 --- Deposition condition --- p.4-13 / Chapter 4.5.1 --- Deposition power --- p.4-15 / Chapter 4.5.2 --- Deposition pressure --- p.4-13 / Chapter 4.5.3 --- Annealing temperature --- p.4-18 / Chapter 4.5.4 --- Substrate temperature --- p.4-21 / Chapter 4.5.5 --- Conclusion --- p.4-26 / References --- p.4-29 / Chapter Chapter 5 --- Failed attempts of MgB2 films fabrication by in situ method / Chapter 5.1 --- In-situ method --- p.5-1 / Chapter 5.2 --- Additional FTS guns with Mg target --- p.5-2 / Chapter 5.3 --- Diode sputtering --- p.5-4 / Chapter 5.4 --- Co-evaporating fabrication --- p.5-6 / Chapter Chapter 6 --- Conclusion --- p.6-1

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For thesis abstract select View Thesis Title, Contents and Abstract

The inert gas ion bombardment of solid surfaces has found many uses in the field of analytical chemistry. In one method of spectrochemical analysis, inert gas ion bombardment in a glow discharge is used to produce an atomic vapor, representative of the sample bulk, which is analyzed using atomic absorption techniques. Gas jets directed at the sample surface during the discharge increase the removal rate of sample material from the surface. Such bombardment of solid surfaces results in changes to the surface which are visually evident in the formation of craters and surface deposits. This thesis was designed to gain a better understanding of the changes in a brass surface caused by jet-enhanced sputtering. Electron spectroscopy for chemical analysis (ESCA) is used to study selected regions of the surface. Changes in chemical composition were observed as successive atomic layers were removed from the sample. The results of this investigation indicate that the effects of ion bombardment can be explained in terms of the selective sputtering of one bulk component over another. The surfaces of the sputtered craters were found to be depleted of the higher sputtering yield component, Zn, when compared to the bulk composition. In a deposit, the component with the highest sputtering yield was found to be more concentrated in layers closest to the bulk material. The component with the lowest sputtering yield was found at relatively higher concentrations nearest the deposit surface. The component with the higher sputtering yield is selectively sputtered first during the glow discharge, and consequently is deposited with a higher concentration closest to the bulk, the converse being true for the lowest sputtering yield component. / Graduation date: 1993

Dissertation (Ph.D.)--University of Toledo, 2009. / Typescript. "Submitted as partial fulfillment of the requirements for the Doctor of Philosophy in Physics." Bibliography: leaves 132-148.

Thesis (Ph. D.), Oregon Graduate Institute of Science & Technology, 1996.

Thesis (M.S.)--Rochester Institute of Technology, 2006. / Typescript. Includes bibliographical references (leaves 145-146).