Reduction of dislocation density in α-Ga2O3 epilayers via rapid growth at low temperatures by halide vapor phase epitaxy

Abstract

We demonstrate that the dislocation density in α-Ga2O3 epilayers is markedly reduced via rapid growth at low temperatures by halide vapor-phase epitaxy. An α-Ga2O3 epilayer grown on (0001) sapphire at a high growth rate of 34 μm h−1 and a low temperature of 463 °C exhibited a dislocation density of 4 × 108 cm−2, which was approximately 1/100 of that in a conventional film. It is likely that the three-dimensional surface morphology developed during the growth enhanced the bending of the dislocations to increase the probability of pair annihilation. The combination of this technique with thick film growth and epitaxial lateral overgrowth resulted in a further low dislocation density of 1.1 × 107 cm−2.