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) s ubstrates using He supersonic beams seeded with NH3. The ALN films wer e used as buffer layers for GaN growth at 800 degrees C. We estimate 3 9% incorporation of the NH3 molecules impinging on the substrate surfa ce during GaN film growth. High structural quality of the epitaxial Ga N layers was confirmed by transmission electron microscopy and electro n 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.