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 -Ga 2 O 3 epilayers is markedly reduced via rapid growth at low temperatures by halide vapor-phase epitaxy. An α -Ga 2 O 3 epilayer grown on (0001) sapphire at a high growth rate of 34 μ m h −1 and a low temperature of 463 °C exhibited a dislocation density of 4 × 10 8 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 × 10 7 cm −2 .