INFRARED AND PHOTOELECTRON-SPECTROSCOPY OF SEMIINSULATING SILICON LAYERS

Infrared (IR) spectroscopy, X-ray-induced photoelectron spectroscopy ( XPS) and electron microprobe analysis (EMA) were used to study semi-in sulating polycrystalline silicon layers (SIPOS) obtained by chemical v apor deposition (CVD) from SiH2 and N2O gases. A mean 'bulk' oxygen co ncentration determined by EMA ranged from 16 to 50 at.%. The position of the Si-O-Si asymmetric stretching band indicates an oxygen-rich pha se with a greater oxygen concentration than the mean bulk oxygen conce ntration determined by EMA technique. In the frame of a two-phase mode l 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 absor ption intensity of the Si-O-Si stretching vibration mode. We obtained a good agreement with EMA results. The two-phase model is strongly sup ported by the photoelectron spectroscopy results. (C) 1998 Elsevier Sc ience B.V. All rights reserved.