Revealing two components of oxidant flux for thermal oxidation of silicon contrary to several models

Abstract

Thermal oxidation of silicon is usually described by the Deal–Grove model with its linear-parabolic relationship between oxide thickness and time deduced from Evans’ stationary basic approach. In order to improve the relationship, other models add correction terms to the Deal–Grove expression. However, none of these models have gained widespread acceptance as being able to describe all relevant influences. In this work, another approach was chosen where experimental data given by Blanc were used to be fitted to arbitrary functions. This procedure does not involve any hypotheses or models of oxidation. Quite the contrary, the derived coefficients of the fit functions enable conclusions with respect to underlying physical processes. Two main conclusions could be drawn: The interfacial oxidant flux comprises two distinct components. One of them does not depend on time, and its value equals to 2.5 × 1012 cm−2 s−1 O2 molecules. The other term increases reciprocally with the positive square root of time. Results clearly show the parameters, which are presupposed as constants, are variables. Hence, the fundamental Deal–Grove model does not adequately formulate the oxidation process.