The microscopic mechanisms of O2 diffusion in compressively strained high-density silicon oxides were investigated based on first-principles total-energy calculations. It was found that, both in high-density α-quartz and in α-cristobalite, the calculated incorporation energies and energy barriers increase with increase of oxide density. Independent of the structure of oxides, the calculated activation energies increase with increasing density. Furthermore, the calculated activation volumes suggested that the oxidation retardation by the oxidation-induced strain was due to the retardation of O2 diffusion in the high-density region, qualitatively consistent with experimental results.

A First-Principles Study of O2 Incorporation and its Diffusion in Compressively Strained High-Density Silicon Oxides. T.Akiyama, K.Kawamoto, H.Kageshima, M.Uematsu, K.Nakamura, T.Ito: Thin Solid Films, 2006, 508[1-2], 311-4