Oxidation-enhanced or retarded diffusion and the growth or shrinkage of oxidation-induced stacking faults in silicon

An analysis of the conditions for obtaining oxidation-enhanced or retarded dopant diffusions (OED or ORD), in accordance with the stacking fault growth/shrinkage phenomena, is carried out for the oxidation of Si by assuming that vacancy and Si self-interstitials coexist at high temperatures and that during oxidation a local equilibrium of point defects is attained. It is shown that the Sb ORD data can be explained quantitatively. Under most oxidation conditions the SiO2-Si interface acts as a source of Si self-interstitials, but at sufficiently high temperatures and long oxidation times the SiO2-Si interface behaves as a sink for Si self-interstitials (or equivalently as a source of vacancies). We suggest a model for this sink behavior in terms of the formation of SiO molecules at the interface and of their subsequent diffusion into the SiO2 film.