A new approach to the direct growth of low-dislocation-density AlxGa1-xN single crystal films on highly mismatched substrates was proposed. 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 mid-106/cm2 values; which was lower than that of films, grown directly onto the 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