Adsorption Sites and Nucleation in Materials Deposition on Silicon and Hydrogen-Terminated Silicon Surfaces

9424296 Bent The goal of this research is to obtain an atomic and molecular level understanding of film nucleation on silicon substrates through a combination of infrared(IR) vibrational spectroscopy and scanning tunneling microscopy(STM). By combining IR with STM, a number of important issues in materials deposition and etching on silicon surfaces -- issues which are fundamental to understanding current microelectronics processes and to developing future technologies will be addressed definitively. Initially the focus will be on exploring the limits of the approach with emphasis on the GaAs/Si system as well as emphasis on the oxidation of silicon. The GaAs/Si system will test the limitations of the experimental approach since this is a system where the IR intensities are expected to be particularly weak. Silicon oxidation will also be studied both because of its technological importance and because it represents a system where high quality and interesting IR results at low frequencies using CoSi2-implanted silicon samples can be obtained. The systems that will be investigated include: oxidation of Si(100) by water and by ethanol as a model system for the TEOS (tetraethoxysilane) MOCVD process. %%% The characterization techniques used in this research provide site specific 'fingerprints' of bonding at surfaces, and the fingerprint from each of these techniques places constraints on the interpretation of the other which permits more definitive conclusions than would be possible from either of the techniques alone. Because of the significance of these materials for electronic and photonic applications, it is important to study the details of elementary chemical and physical processes, and to understand fundamental features of structure/property relationships. An important feature of the program is the training of students in a fundamentally and technologically significant area of materials research. ***