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Simulation And Modelling Of Thin Film Phi(Rho-Z) Curves For Electron Probe Microanalysis, Ka Shing Chan
Simulation And Modelling Of Thin Film Phi(Rho-Z) Curves For Electron Probe Microanalysis, Ka Shing Chan
Digitized Theses
Quantitative analysis of homogeneous bulk unknowns using an electron probe microanalyzer requires the accurate knowledge of the depth distributions of x-ray production ({dollar}\phi{dollar}({dollar}\rho{dollar}z) curves). Straight line behaviour is observed in the plot of ln{dollar}\phi{dollar}({dollar}\rho{dollar}z) versus ({dollar}\rho{dollar}z){dollar}\sp2{dollar} for most experimentally measured data. Monte Carlo calculations can be used to simulate {dollar}\phi{dollar}({dollar}\rho{dollar}z) curves. However, ln {dollar}\phi{dollar}({dollar}\rho{dollar}z) versus ({dollar}\rho{dollar}z){dollar}\sp2{dollar} plots of these {dollar}\phi{dollar}({dollar}\rho{dollar}z) curves, in general, are nonlinear and concave downward. By introducing the concept of electron straggling into a multiple scattering Monte Carlo model, agreement with the behaviour of experimental curves is achieved.;Electron probe microanalysis can also be used for the characterization …
High Temperature X-Ray Diffraction Investigation Of The Beta-(Bismuth(2) Oxygen(3))(1-X)(Strontium Oxide)(X) Solid Solution, Edward Andrew Payzant
High Temperature X-Ray Diffraction Investigation Of The Beta-(Bismuth(2) Oxygen(3))(1-X)(Strontium Oxide)(X) Solid Solution, Edward Andrew Payzant
Digitized Theses
To investigate the controversial {dollar}\beta\sb1\leftrightarrow\beta\sb2{dollar} phase transformation in the {dollar}\beta{dollar}-{dollar}\rm (Bi\sb2O\sb3)\sb{lcub}1-x{rcub}(SrO)\sb{lcub}x{rcub}{dollar} phase, a series of compositions across the phase were prepared by conventional grinding, pressing and firing ceramic techniques. Electrical conductivity measurements demonstrated that the samples were comparable to those used in other laboratories. X-ray diffraction analysis confirmed that the cations are located on a hexagonal sublattice, but details of the anion sublattice could not be resolved, because of the low X-ray scattering factor of {dollar}\rm O\sp{lcub}2-{rcub}.{dollar};The compositional dependence of the lattice parameters of the hexagonal crystal structure of the {dollar}\beta{dollar}-{dollar}\rm (Bi\sb2O\sb3)\sb{lcub}1-x{rcub}(SrO)\sb{lcub}x{rcub}{dollar} phase, which was determined at {dollar}27\sp\circ\rm C{dollar} using …
Compositional Analysis Of Gate Dielectric Films, Hongtao Tang
Compositional Analysis Of Gate Dielectric Films, Hongtao Tang
Digitized Theses
Oxynitride has recently drawn attention as a candidate gate dielectric material for deep sub-micron devices, e.g. MOSFET's. Since the oxide growth rates in pure oxygen are high, efforts to scale down device dimensions with high quality ultrathin ({dollar}<{dollar}100A) SiO{dollar}\sb2{dollar} films are encountering some difficulties. Recently, it has been found that oxynitride films fabricated directly by a N{dollar}\sb2{dollar}O-rapid thermal processing method exhibit improved electrical properties compared to SiO{dollar}\sb2{dollar} films. Structural analysis for such oxynitride films is necessary in order to understand the physical reasons behind the observed improvements.;Nuclear reaction analysis combined with a chemical step-etching method was performed to depth profile nitrogen quantitatively in N{dollar}\sb2{dollar}O-RTP grown oxynitride films. The oxynitride dielectric composition dependence on growth conditions in a rapid thermal processing system was also investigated by nuclear reaction analysis. It is found that most N in the oxynitride films accumulates in a region close to the interface (less than 25 A from the interface in the oxynitride). Both N concentration and film thickness increase with temperature. Furthermore, a UHV initial growth study of oxynitride films on a Si(100) substrate was carried out by nuclear reaction analysis and Auger electron spectroscopy. The results clearly confirm that the nitrogen involvement occurs primarily before an oxynitride film thickness of {dollar}\sim{dollar}25 A is developed, and the subsequent film growth is dominated by oxidation. For the first time, it is found that there is a special growth period at the very beginning during which nitridation (with no simultaneous oxidation) dominates the growth process. It is speculated that the phenomenon results from a competition between reactions of Si with O and N. The dependence of film growth on temperature is such that below 950{dollar}\sp\circ{dollar}C, there is little nitrogen incorporated in the oxide film.
Chemistry Of Antiwear Films By X-Ray Absorption Spectroscopy, Zhanfeng Yin
Chemistry Of Antiwear Films By X-Ray Absorption Spectroscopy, Zhanfeng Yin
Digitized Theses
The antiwear and antioxidant additives, zinc dialkyldithiophosphates (ZDDPs), are an essential ingredient in engine oil formulations, and have been in use for many years. These additives function by forming antiwear films on surfaces in sliding contact, and thus reduce friction and wear. Among the surface techniques employed, X-ray absorption spectroscopy (including EXAFS and XANES) has been mainly used because of its high resolution, low detection limit and non-destructive characteristics.;This is the first time that P and S L-edge XANES spectroscopy has been used to analyze antiwear films and thermal films. About two hundred antiwear films and thermally prepared films have …
The Growth And Magnetic Properties Of Metal Overlayer Systems: Palladium/Copper(100), Iron/Aluminum(100) And Iron/Sulfur/Gallium Arsenide(100), Geoffrey William Anderson
The Growth And Magnetic Properties Of Metal Overlayer Systems: Palladium/Copper(100), Iron/Aluminum(100) And Iron/Sulfur/Gallium Arsenide(100), Geoffrey William Anderson
Digitized Theses
Epitaxial growth of a metal overlayer on an appropriate substrate can be utilized to create systems which exhibit unique chemical and magnetic properties. This thesis will outline the investigation of three metal overlayer systems: Pd/Cu(100), Fe/Al(100) and Fe/S/GaAs(100). In the Pd/Cu(100) system the growth and evolution of defects were examined using re-emitted positron spectroscopy. Two changes in growth mode were observed: at 0.5 monolayer (representing the completion of the first alloy layer) and 1 monolayer Pd coverages (representing the start of bulk Pd growth). The bulk Pd film was observed to contain 1% vacancy-type defects. In the Fe/Al(100) system the …
The Initial Interaction Of Water Vapour With Magnesium And Magnesium Alloy Surfaces, Steven Joseph Splinter
The Initial Interaction Of Water Vapour With Magnesium And Magnesium Alloy Surfaces, Steven Joseph Splinter
Digitized Theses
The initial interaction of water vapour with polycrystalline magnesium and magnesium alloy surfaces has been quantitatively followed from the earliest stage using Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The fitting of AES data to theoretical models suggested that a three-stage oxidation behaviour was operative on pure Mg surfaces: (1) dissociative chemisorption during doses up to {dollar}{lcub}\approx{rcub}0.7{dollar} langmuir (L) (1L = {dollar}1.3\times10\sp{lcub}-4{rcub}{dollar} Pa{dollar}\cdot{dollar}s); (2) oxide nucleation and growth which is complete by {dollar}{lcub}\approx{rcub}5{dollar}L at an average island height of four monolayers; and (3) bulk thickening after coalescence of the oxide islands. The bulk thickening stage was adequately described …
Surface Modifications Of Silicon Induced By Low Energy Reactive Ion Bombardment, Wayne Harold Chang
Surface Modifications Of Silicon Induced By Low Energy Reactive Ion Bombardment, Wayne Harold Chang
Digitized Theses
The effects of low energy reactive ion bombardment of semiconducting silicon material have been investigated by X-ray photoelectron spectroscopy. The residual surface damage induced by a conventional fluorocarbon plasma reactive ion etching of silicon consisted of a uniform fluorocarbon deposited film approximately 4nm in thickness which covered a silicon compound reaction layer. This reaction layer was comprised of silicon oxides, carbide and fluorosilyl species distributed in depth to approximately 2nm. The removal of the residuel surface damage was accomplished by an ozone oxidation plus a wet oxide chemical etching step processing and monitored by surface charge spectroscopy. This residual surface …
Fabrication Of Indium Phosphide Misfet, Raymund Wai-Man Kwok
Fabrication Of Indium Phosphide Misfet, Raymund Wai-Man Kwok
Digitized Theses
The presence of excessive energy states in the bandgap of III-V semiconductor surfaces is commonly found and has considerably hindered the development of III-V semiconductor technology. Although InP metal-insulator-semiconductor field effect transistors (MISFETs) are attractive switching and driving elements for the InP-based optoelectronic devices which have been widely used for communication applications, interface states of the dielectric/InP structure are known to cause surface Fermi level pinning and drain current drifting, a fact which causes the MISFETs to be unacceptable for any practical usage. In this study, we used a wide range of surface and interface analytical techniques to investigate a …
Electrochemical Properties Of Passive Films On 440c Stainless Steel, Timothy Lawrence Walzak
Electrochemical Properties Of Passive Films On 440c Stainless Steel, Timothy Lawrence Walzak
Digitized Theses
The properties of passive films formed on 440C stainless steel were investigated using advanced electrochemical techniques for the purpose of establishing a method to measure film stability directly in passivation baths. Electrochemical measurements were sensitive to the passive film properties and were able to quantify the effect of cooling rate on passive film stability. The various techniques used--linear polarization, AC impedance, small amplitude cyclic voltammetry (SACV), and coulostatic transient measurements--provided results that exhibited excellent agreement with the AC impedance technique providing the most information about the interfacial reactions. Full electrochemical characterization of the passive film stability required an evaluation of …
Determination Of Absorption And Atomic Number Corrections In Electron Probe Microanalysis For Electron Energies Below 15 Kev, Lubomir Parobek
Determination Of Absorption And Atomic Number Corrections In Electron Probe Microanalysis For Electron Energies Below 15 Kev, Lubomir Parobek
Digitized Theses
No abstract provided.
Evaluation And Characterization Of Surface Roughness By Ellipsometry, Edmond Che-Hung Chan
Evaluation And Characterization Of Surface Roughness By Ellipsometry, Edmond Che-Hung Chan
Digitized Theses
No abstract provided.