9420558 Holl This research is focused on developing a better understanding of the atomic scale structure of the silicon/silicon oxide interface and the chemical reactions which occur at this interface. To accomplish these goals, methods are developed for making silicon/silicon oxide interfaces of well-defined structure to serve as model spectroscopic systems. The model interfaces synthesized provide excellent test systems for crHically examining the assumptions and assignments used when interpreting data collected from standard themmal oxide interfaces, an essential component of most microelectronic devices. The interfaces being synthesized are also interesting from the perspective of a priori control of solid structure. Synthetic methods are proposed which allow chemical tuning of the interface and formation of metastable thin films of silicon oxide. Analysis of the stepwise formation of a film using surface science techniques avoids a common problem of precursor to solids chemistry, obtaining meaningful analytical data from the solid formed. %%% The interface between crystalline and amorphous silicon dioxide plays a critical role in microelectronic devices and has been the subject of intense research for over 40 years. Advances in information and communications have been directly coupled with the development of better methods of materials preparation. As silicon oxide film dimensions shrink from about 1000 to 50-100 A, design and understanding of the composition of the interface layer becomes of critical importance. This research is focused on developing a better understanding of the atomic scale structure of the silicon/silicon oxide interface and the chemical reactions which occur at this interface.