Bound oxygen influence on the phase composition and electrical properties of semi-insulating silicon films

Abstract

The purpose of this work is to establish of the bound oxygen effect on the phase composition of the Semi-Insulating Polycrystalline Oxygen-doped Silicon (SIPOS) films by means of three independent methods: X-ray diffraction (XRD), Ultrasoft X-ray Emission Spectroscopy (USXES) and Raman spectroscopy, also on their electrophysical properties, depending on the relative oxygen content in the gas mixture flow (γ=N2O/SiH4) of the plasma reactor during the chemical vapor deposition of submicron SIPOS layers on monocrystalline silicon wafers. The increase in the oxygen content in SIPOS layers from γ=0 to maximum at γ=0.15 leads to the reduction of Si nanocrystals size from ~75 nm to 2–5 nm, submerged in amorphous matrix. Oxygen is contained in the bound form of silicon-oxygen clusters SiOSi3 type in the amorphous silicon matrix without SiO2 formation. These nonlinear qualitative and quantitative changes in the atomic structure of the SIPOS layers under the influence of bound oxygen increase not only the resistivity of the films by two orders of magnitude but also the activation energy of conductivity in comparison with silicon at the temperatures above room temperature. © 2020 Elsevier Ltd