Infrared and photoelectron spectroscopy of semi-insulating silicon layers

Infrared (IR) spectroscopy, X-ray-induced photoelectron spectroscopy (XPS) and electron microprobe analysis (EMA) were used to study semi-insulating polycrystalline silicon layers (SIPOS) obtained by chemical vapor deposition (CVD) from SiH(2) and N(2)O gases. A mean 'bulk' oxygen concentration determined by EMA ranged from 16 to 50 at.%. The position of the Si-O-Si asymmetric stretching band indicates an oxygen-rich phase with a greater oxygen concentration than the mean bulk oxygen concentration determined by EMA technique. In the frame of a two-phase model of SIPOS composed of only pure silicon and homogeneous oxide phases, we calculated the mean bulk oxygen concentration using the density of the oxygen-silicon bonds derived from the normalized integrated absorption intensity of the Si-O-Si stretching vibration mode. We obtained a good agreement with EMA results. The two-phase model is strongly supported by the photoelectron spectroscopy results. (C) 1998 Elsevier Science B.V. All rights reserved.