In this study we apply an interface sensitive ellipsometry technique to study the evolution of the Si–SiO2 interface as a function of high temperature annealing (750–1100 °C). Essentially, the ellipsometry technique embodies the use of liquids that refractive index match with the bulk film thereby removing the optical response of the overlayer and greatly enhancing sensitivity to the interface. According to both time and temperature of anneal, distinct modes of behavior are observed for the evolution of the interface. For short anneal times a rapid change in the interface is observed that correlates with the disappearance of protrusions, followed by a slower change that correlates with the disappearance of the suboxide. At high temperatures viscous relaxation dominates, while at low temperatures the suboxide reduction is apparent. A model for the interface in terms of chemical and physical interface processes is proposed and model parameters are compared with literature results.

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