The growth of GaN with an AlGaN/GaN heterostructure was carried out, on a (111) Si substrate, by using selective area metal-organic vapour phase epitaxy methods. The GaN obtained was a trapezoidal stripe having (1¯1▪1) facets on the sides and a (00▪1) facet on the top. The distribution of the Al composition over the facets was investigated by performing cathodoluminescence analyses as a function of the position. The surface diffusion of Ga on the (00▪1) AlGaN facet was studied under various growth conditions. It was found that the diffusion length was enhanced by increasing the growth temperature or lowering the Al composition. From the temperature dependence of the diffusion length, the activation energy of the Ga species was estimated. The results depended upon the Al composition: with a value of 1.23eV for x = 0.05, a value of 1.84eV for x = 0.10 and a value of 2.72eV for x = 0.15.

The Surface Diffusion of Ga on an AlGaN/GaN Stripe Structure in the Selective MOVPE. T.Narita, Y.Honda, M.Yamaguchi, N.Sawaki: Physica Status Solidi B, 2006, 243[7], 1665-8