Extended fine structure of auger spectra of thermally oxidized silicon surface

Abstract

The data are presented on the evolution of the shape and position of the L23VV Auger line for the surface of single-crystal silicon Si(111) during its thermal oxidation. The fine structure of the high-energy region of the Auger spectrum is found to be related to the loss of energy by Auger electrons for plasmon excitation and electronic interband transitions, while the low-energy region may be associated with the effect of extension fine Auger structure (EXFAS). By the example of Si atoms in a thin surface layer of SiO2, it is shown that, similarly to studying the ordinary oscillations of the EXAFS absorption spectra, the EXFAS technique can be used to solve the problems of the restoration of the local environment of atoms. The interatomic distances calculated using the Fourier transform of the right-hand sides of the Auger spectra (EXFAS spectra) for the pure and oxidized silicon surfaces appear to be 2.2 and 1.7 A, respectively, thereby coinciding with the published values within determination error.