SiO, valence band near the SiO,/Si(lll) interface

The changes in X-ray excited valence bands of silicon oxide with progress of oxidation of a Si( 111) surface in 1 Torr dry oxygen at 600-800°C were studied at initial stage of oxidation. The following results were obtained: (1) the energy level of the top of the valence band within 0.9 nm from the interface is different from that of the bulk silicon oxide by about 0.2 eV and (2) the valence band discontinuity at the interface changes periodically with the interface structures.