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 Si---O 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.