The kinetics of oxidation: Refinements for silicides, silicon and other materials

Abstract

The present considerations are based on two earlier publications concerning oxidation. Both of these added to the usual derivation of the linear-parabolic kinetics modifications based on variations in the chemical activity of the material being oxidized, as a result of the very process of oxidation itself. In this previous work, it was assumed that the equilibrium oxygen concentration, below which oxidation becomes impossible, was a constant. This is conceptually wrong when the activity of the material being oxidized is not constant. The correct solutions for the kinetics of oxidation have been derived now and are shown not to deviate significantly from the previous solutions under most usual circumstances. In one of the two cases being examined, the formation of SiO2 over silicide films, the previous work assumed steady-state conditions. The process of establishing steady state has now been analysed as well. For a silicide such as WSi2 it is shown that steady-state conditions are reached within an extremely short time. © 1992 Taylor & Francis Group, LLC.