The self-diffusion of Si in thermally grown SiO2 near the SiO2/Si interface during thermal oxidation process was studied using isotopic heterostructures (natSiO2/28Si) as a function of the oxidation temperature, the oxidation time, and the fraction of O in the ambient gas. The Si self-diffusivity near the SiO2/Si interface during oxidation was found to be larger than the thermal Si self-diffusivity by more than one order of magnitude. This enhancement indicated that Si species were emitted from the SiO2/Si interface and diffused into SiO2 during oxidation, as was predicted by recent theoretical studies.

Generation of Excess Si Species at Si/SiO2 Interface and Their Diffusion into SiO2 during Si Thermal Oxidation. K.Ibano, K.M.Itoh, M.Uematsu: Journal of Applied Physics, 2008, 103[2], 026101