A simple growth technique for the reduction of threading dislocation density of AlN under Ga irradiation during initial growth stage was proposed. In X-ray rocking curve measurements, line-width of (00▪2) and (1¯1▪2) diffraction for 500nm-thick AlN were 100 and 260arcsec, respectively. The threading-dislocation density of the AlN was estimated to be about 8 x 108/cm2 from the symmetrical and asymmetrical diffractions. The AlGaN/AlN multi-quantum well structure was grown on the high-quality AlN layer. By cathodoluminescence mapping measurements, intense deep-UV emission at 246nm was observed from the area of more than 90%. The low dislocation density AlN was an ideal template for deep-UV optical devices.

Growth of Low-Dislocation-Density AlN under Ga Irradiation. A.Nakajima, Y.Furukawa, H.Yokoya, S.Yamaguchi, H.Yonezu: Japanese Journal of Applied Physics, 2006, 45[4A], 2422-5