Kinetics of thermal oxidation of AlAs in water vapor

Abstract

We have investigated the lateral thermal oxidation of AlAs in water vapor in vertical cavity surface emitting laser structures. At low temperatures and short oxidation times, oxide growth was found to be reaction rate limited. Conversely, diffusion across the oxide was the rate controlling mechanism at higher temperatures and longer oxidation times. Lasers are typically processed at intermediate values of temperatures and time. The observed growth can be modeled by rate equations by which the two component growth mechanisms can be separated. Activation energies of 1.6 and 0.8 eV were determined for the reaction rate and diffusion limited mechanisms, respectively.