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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 …
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 …