Infrared Spectroscopy of Si(111) and Si(100) Surfaces after HF Treatment: Hydrogen Termination and Surface Morphology.

Multiple internal infrared reflection spectroscopy has been used to identify the chemical nature of chemically oxidized and subsequently HF stripped silicon surfaces. These very inert surfaces are found to be almost completely covered by atomic hydrogen. Results using polarized radiation on both flat and stepped Si(111) and Si(100) surfaces reveal the presence of many chemisorption sites (hydrides) that indicate that the surfaces are microscopically rough, although locally ordered. In particular, the HF-prepared Si(100) appears to have little in common with the smooth H-saturated Si(100) prepared in ultra-high vacuum.