9701091 Seiberling This project aims for greater fundamental materials science understanding of issues surrounding surfactant-mediated epitaxy. For example, Sn and Sb are surfactants that have opposite influences on film growth, but the difference is not understand on the basis of chemical bonding. This proposal address the microscopic bonding arrangement of Sn and Sb on Si(100) and their interaction with a growing Ge film. Transmission ion channeling, which can determine the bonding sites of atoms on a surface with a resolution of better than 0.01 nm, will be used to follow the positions of the surfactant and Ge atoms from the initial bonding site, with Ge on top of the surfactant layer, through the surfactant/adatom exchange, leading eventually to the final state. %%% The project addresses issues in a forefront research area of materials science. The research will contribute basic materials science knowledge at a fundamental level to important aspects of electronic/photonic devices and integrated circuitry, in general. Additionally, the fundamental knowledge and understanding gained from the research is expected to contribute to improving the performance of advanced devices and circuits by providing a fundamental understanding and a basis for designing and producing improved materials, and materials combinations. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***