Modelling of radial steam oxidation of AlAs layers in cylindrically symmetric mesa structures of vertical-cavity surface-emitting lasers

During the last several years selective steam oxidation process has evolved into a key technology in fabrication of high-performance vertical-cavity s urface-emitting lasers (VCSELs). In the present paper, kinetics of AlAs ste am oxidation process in cylindrically symmetric VCSEL mesa structures is in vestigated theoretically. Compact analytical formulae describing the oxidat ion process are derived and discussed. The process parameters are extracted from existing experimental data. The parameters are found to be strongly d ependent on the AlAs layer thickness and temperature. It is shown that sign ificant differences exist between the predictions of the cylindrical model and those of widely used one-dimensional Cartesian model. Our detailed mode l can therefore be very important for achieving a good control of the oxida tion process in fabrication of modern VCSELs.