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

We report an AIN 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 AIN crystalline quality. By optimizing the thickness of the interlayer, the TD density and surface roughness can be reduced simultaneously.