Reaction of Oxygen with Si(111) and (100): Critical Conditions for the Growth of SiO2

Abstract

The reactions of oxygen (02) with the clean Si ( l l!) and (100) surfaces have been studied at high temperatures (890~176 for oxygen pressures between 5 • 10-5 and 5 • 10-2 Torr. The critical conditions involving oxygen pressure and substrate temperature which are necessary for the growth of SiO2 to occur on these Si surfaces have been determined, and are found to be independent,of substrate orientation and doping type under the conditions tudied. The observed critical conditions for growth are consistent with a theoretical model which focuses on the kinetics of SiO2 cluster growth and on the thermodynamics of the competing etching reaction leading to production of SiO. Evidence is presented for epitaxial growth on Si(100) of cubic SiOf, B-cristobalite. The react ion of oxygen (02) with the clean surface of silicon leading to the thermal growth of thin films of SiO ~ continues to be of considerable interest (1) both from a technological point of view and also as a source of fundamental information on gas-surface in-teractions and on thin film growth processes. We re-port here on our studies o f the reactions of '02 with