High Quality A1N with a Thin Interlayer Grown on a Sapphire Substrate by Plasma-Assisted Molecular Beam Epitaxy

We report an A1N epi-layer grown on sapphire by plasma-assisted molecular beam epitaxy with a thin interlayer structure. The effects of growth mode on threading dislocations (TDs) and surface morphology are studied. Then an interlayer structure grown under a V/III ratio of 1 is adopted to improve the A1N crystalline quality. By optimizing the thickness of the interlayer, the TD density and surface roughness can be reduced simultaneously.