High Quality Deposition of SiO2 Downstream from a Microwave Discharge

Abstract

ABSTRACTHigh quality stoichiometric silicon dioxide films have been deposited on silicon substrates at low pressure(1.0Torr) and low temperatures(≤ 350C) downstream and at a right angle to a microwave discharge. The deposition was accomplished by injecting 2% SiH4 in helium downstream of a N20 microwave generated discharge. Infrared spectroscopic analysis has determined that no detectable SiH, SiOH, Si-H2o or SiN chemical complexes were present in any films deposited at temperatures above 250C. Rutherford Backscattering and Forward Scattering Detection Spectroscopy were used to determine the elemental composition and hydrogen concentration in the films, respectively. The thick films were found to be stoichiometric with no detectable elemental impurities. The measured hydrogen concentration in the thin films was comparable to that measured in thermally grown Si0 2 of approximately the same thickness. The quality of the thin oxides(<30nm) has been determined by fabricating MOS devices from the Si-Si0 2 system.