Influence of Low Temperature-Grown GaAs on Lateral Thermal Oxidation of Al_0.98Ga_0.02As

Abstract

The lateral thermal oxidation process of Al 0.98 Ga 0.02 As layers has been studied by transmission electron microscopy. Growing a low-temperature GaAs layer below the Al 0.98 Ga 0.02 As has been shown to result in better quality of the oxide/GaAs interfaces compared to reference samples. While the later have As precipitation above and below the oxide layer and roughness and voids at the oxide/GaAs interface, the structures with low-temperature have less As precipitation and develop interfaces without voids. These results are explained in terms of the diffusion of the As toward the low temperature layer. The effect of the addition of a SiO 2 cap layer is also discussed.