Generation of excess Si species at Si/SiO₂ interface and their diffusion into Si/O₂ during Si thermal oxidation

Si self-diffusion in thermally grown Si O2 near the Si O2 Si interface during thermal oxidation process was studied using isotopic heterostrucutures (Sinat O2 Si28) as a function of the oxidation temperature, the oxidation time, and the fraction of oxygen in the ambient gas. The Si self-diffusivity near the Si O2 Si interface during oxidation was found to be larger than the thermal Si self-diffusivity by more than one order of magnitude. This enhancement indicates that Si species are emitted from the Si O2 Si interface and diffused into Si O2 during oxidation, as has been predicted by recent theoretical studies.