Thermal oxidation of silicon: Chemisorption and linear rate constant

Abstract

This is the first of a series of three papers which, by introducing new concepts and new formulations that are consistent with experimental observations, attempt to treat a number of topics related to the kinetics and the mechanisms of the thermal oxidation of silicon. The present paper deals with the surface reaction aspect of oxidation. A new oxide growth law has been formulated to be consistent with the observed power-law pressure dependence of interface reaction kinetics. Then the subject of chemisorption, proposed here as an intermediate step of the thermal oxidation of silicon, is treated at length. It is shown, from a first-principles analysis, that the energy of chemisorption should vary approximately logarithmically with the amount of chemisorption, that this leads to an adsorption isotherm which is related to the oxygen pressure by a power law, and that the exponent of the power law should vary linearly with temperature within a reasonable span. The effects of substrate doping and of substrate damage are also analyzed.