Features of atomic and electronic structure of oxides on porous silicon surface according to XANES data

Based on synchrotron research of the fine structure main parameters of SiL _{2, 3} X-ray absorption edges (X-ray absorption near edge structure (XANES)) in porous silicon on boron-doped Si(100) wafers, the thickness of the surface oxide layer and the degree of distortions of the silicon-oxygen tetrahedron in this layer were estimated. The thickness of the oxide layer formed on the amorphous layer coating nanocrystals of porous silicon exceeds the thickness of the native oxide on the surface of Si(100) : P and Si(100) : B single-crystal (100) silicon wafers by several times. Distortion of the silicon-oxygen tetrahedron, i.e., the basic unit of silicon oxide, is accompanied by Si-O bond stretching and an increase in the angle between Si-O-Si bonds.