Layers of AlN and GaN were grown onto 4º off-axis 6H-SiC (00•1) substrates by using He supersonic beams that were seeded with NH3. The AlN films were used as buffer layers for GaN growth at 800C. It was estimated that 39% of the NH3 molecules, which impinged on the substrate surface during GaN film growth, were incorporated. The high structural quality of the epitaxial GaN layers was confirmed by transmission electron microscopy and electron channelling patterns. The GaN films, which had a thickness of about 105nm, had a defect density of about 2 x 1010/cm2.

V.M.Torres, M.Stevens, J.L.Edwards, D.J.Smith, R.B.Doak, I.S.T.Tsong: Applied Physics Letters, 1997, 71[10], 1365-7