The (100) silicon silicon dioxide interface. II. The Si LVV Auger lines

The electronic state, calculated by a slab semiempirical tight-binding method, is utilized to calculate the Si L2,3VV Auger transition line shapes. These calculations are carried out for (a) the free Si(100) surface, (b) the 2 × 1 reconstructed surface, (c) the oxygen chemisorbed surface (for both atomic and molecular oxygen), and (d) the interface between a thin oxide and Si. New states which are typical of the SiO bonds appear as characteristic peaks corresponding to these states in the Auger spectra. These lie between the positions of the Si peak in the bulk Si and SiO2 and correspond to previously observed experimental peaks. From comparison with the available experimental data, it appears that the initial oxidation is by atomic oxygen rather than by molecular oxygen.