MECHANISMS AND KINETICS OF ROOM-TEMPERATURE SILICON OXIDATION

The microscopic mechanisms of room-temperature silicon oxidation in dr y or wet air are considered. The experimental oxidation kinetics of hy drogen-terminated silicon surfaces can be described by a model of wate r-assisted attack to backbonds of partially oxidized silicon followed by layer-by-layer oxidation. A mechanism, where the rate determining s tep is electron transfer from negatively charged silicon at the Si-SiO 2 interface to adsorbed O-2 at the SiO2 surface, is consistent with th e mathematical structure of the layer-by-layer model. A detailed schem e of electron charge transfer and bond formation in the very early oxi dation stages is proposed. (C) 1997 Elsevier Science B.V.