Growth of AlN and GaN on 6H-SiC(0001) using a helium supersonic beam seeded with ammonia

We have grown AIN and GaN layers on 4 degrees off-axis 6H-SiC (0001) substrates using He supersonic beams seeded with NH3. The ALN films were used as buffer layers for GaN growth at 800 degrees C. We estimate 39% incorporation of the NH3 molecules impinging on the substrate surface during GaN film growth. High structural quality of the epitaxial GaN layers was confirmed by transmission electron microscopy and electron channeling patterns. The GaN films, which had a thickness of similar to 105 nm, contained a defect density of similar to 2 x 10(10) cm(-2). (C) 1997 American Institute of Physics.