INITIAL OXIDATION OF MBE-GROWN SI(100) SURFACES

We have investigated the initial oxidation of MBE-grown Si(100) surfaces with atomic flatness using X-ray photoemission spectroscopy (XPS) and reflection high energy electron diffraction (RHEED). It was found that the MBE-grown surfaces are inert and hardly oxidized even after exposure to molecular oxygen up to 1500 L at room temperature and that the oxygen coverage is saturated at 0.4 ML. At elevated temperatures, however, the surface oxidation was substantially promoted on the atomically flat surface. On the other hand, the oxidation was found to proceed on a deliberately corrugated Si surface prepared by a low temperature MBE growth, even at room temperature.