Effect of bulk growth temperature on antiphase domain boundary annihilation rate in MOCVD-grown GaAs on Si(001)

Abstract

GaAs is a material of interest as a potential buffer layer in future III–V semiconductor-based transistor technologies integrated on Si wafers. The goal of this study was to investigate the effect of growth temperature on the propagation and annihilation of antiphase domain boundaries (APBs) in GaAs films grown on Si(001) by metal-organic chemical vapor deposition (MOCVD). No intentional wafer off-cuts or high temperature pre-growth anneals (>1000°C) were employed as both of these practices complicate integration with other devices. To evaluate the role of growth temperature on the APB evolution, a 200nm thick layer of GaAs was grown on the Si at a fixed temperature of 530°C so that all samples started with the same approximate APB density. Subsequently, 600nm of GaAs was grown at temperatures varying between 530°C and 650°C. Chemical etching combined with scanning electron microscopy (SEM) was used to profile the density of the APBs in each sample as a function of depth. The APB annihilation rate, i.e. the exponential decay rate of APB density with respect to film thickness, increases from 2.6μm−1 to 10.7μm−1 as the growth temperature increases from 530°C to 610°C and then saturates. The increase in annihilation rate with increasing temperatures suggests that the higher temperatures remove kinetic barriers to the reduction of the overall APB interfacial area. An activation energy of 1.1eV was extracted using an Arrhenius relationship and likely corresponds to the energy needed for APBs to kink from {110} to higher-index planes, e.g. {112}. Dark field transmission electron microscopy showed that at higher growth temperatures the APBs can shift from vertical {110} habit planes to {112} planes leading to self-annihilation with sufficient thickness.