Calculated and measured Auger line shapes in SiO2

The Si $L_1{L}_{23}V$, Si $L_{23}\mathrm{VV}$, and O $\mathrm{KVV}$ Auger transitions in Si${\mathrm{O}}_2$ have been measured and compared to calculated line shapes. The measurements were made on thick steam oxides grown on Si (111). The data were corrected for electron loss and spectrometer distortions; the correction scheme is presented. All three Auger transitions are calculated from the same valence-electron density of states which is described in terms of a linear-combination-of-atomic-orbitals molecular-orbital model. X-ray photoelectron spectroscopy and x-ray emission and absorption data are used to determine the orbital energies, populations, and widths. The Auger transition energies are estimated from one-electron calculations including static relaxation and hole-hole repulsion effects. The intensities are estimated from electron densities local to the core hole multiplied by the appropriate atomic Auger matrix element. Three major features are predicted by the calculations for the Si $L_{23}\mathrm{VV}$ and O $\mathrm{KVV}$ transitions and are observed experimentally; two major features are predicted for Si $L_1{L}_{23}V$, only one is observed experimentally because of baseline problems. The calculated absolute energies of all major features agree within 2 eV with experimental values, the relative agreement between peaks within a given line shape is better than 1 eV. The observed intensities of the major features are in reasonable agreement with the calculations but there are some discrepancies thought due to either the matrix elements or the charge densities assumed in the calculations. Considerable intensity in the experimental line shapes between the major peaks, not accounted for in the present calculation, is probably due to shake-up or shake-off satellite structure.