The direct growth technique, using periodically grooved substrates of sapphire(00•1), sapphire(11•0) and 6H-SiC(00•1)Si, was used to grow low dislocation density AlGaN with AlN molar fractions of less than 0.14. The low dislocation densities which were observed in lateral growth areas were of the order of 107/cm2 or less; similar to those in GaN prepared by using the same technique. It was also found that doping Mg into AlGaN films assisted lateral growth very effectively.

Growth Mechanism and Characterization of Low-Dislocation-Density AlGaN Single Crystals Grown on Periodically Grooved Substrates. T.Detchprohm, S.Sano, S.Mochizuki, S.Kamiyama, H.Amano, I.Akasaki: Physica Status Solidi A, 2001, 188[2], 799-802