Effect Of Sb Composition On Lateral Oxidation Rates In Alas1-Xsbx

We demonstrate the effect of antimony (Sb) composition on the oxidation mechanism of AlAs1-xSbx (x < 0.21) layers on GaAs substrates. It has been demonstrated that addition of a group-III element like Ga to AlAs slows the rate of oxidation. In contrast, addition of a group-V element like Sb to AlAs changes the oxidation mechanism in more than one way. The oxidation rate increases with Sb addition, and the oxidation reaction changes from a diffusion-limited mechanism to a reaction-rate-limited mechanism at higher oxidation temperatures. This is attributed to the increase in the permeability of the oxide. Nonuniform segregation of Sb is observed upon oxidation. The activation energy of the oxidation reaction-rate constant initially decreases with the Sb composition upto 10%, further Sb addition increases the activation energy. (C) 2000 American Institute of Physics. [S0003-6951(00)00410-1].