The Si->SiO sub 2 Transformation: Interfacial Structure and Mechanism.

We show that the c-Si->a-SiO sub 2 transformation takes place via an ordered crystalline oxide, whose structure (and hence stoichiometry) are those of a stable, bulk phase of SiO sub 2 namely tridymite. We have deduced a three-dimensional map of atom positions at and near the Si/SiO sub 2 interface and show that a microscopic understanding of this structure elucidates the mechanism for the oxidation of Si.