Oxide degradation during selective epitaxial growth of silicon

Abstract

A derivative of selective epitaxial growth and epitaxial lateral overgrowth, has been devised to create single-crystal silicon on insulator structures. The effect of conditions present in selective epitaxial growth and epitaxial lateral overgrowth on the electrical characteristics of the insulating masking oxides has been studied. It was determined that thin (<150 nm) oxides were attacked by the ambient employed in selective epitaxy. The rate of degradation increased with decreasing oxide thickness and with the addition of silicon-containing species to the gas phase. The observed defect formation may be related to the oxide decomposition during annealing in oxygen-free ambients and the undercutting of masking oxide at the Si-SiO2 interface during the in situ preclean step used in epitaxial processes.