A new approach was proposed for the direct growth of low dislocation density AlxGa1-xN single crystal films on highly mismatched substrates. Four different substrates, basal-plane sapphire (00•1) and (11•0), 6H–SiC(00•1)Si and Si(111), were used. The surface of the substrates was patterned with periodic grooves. In this technique, neither a selective growth mask nor a patterned GaN single crystal film were used. Low dislocation density areas were observed above the trench area and at the boundaries of the terrace and trench areas. The dislocation density was reduced to about 5 x 106/cm2; which was lower, than that in films grown directly onto planar substrates, by at least 2 orders of magnitude.

Low Dislocation-Density AlxGa1-xN Single Crystals Grown on Grooved Substrates. S.Sano, T.Detchprohm, M.Yano, R.Nakamura, S.Mochizuki, H.Amano, I.Akasaki: Materials Science and Engineering B, 2002, 93[1-3], 197-201