Thick layers were grown by means of hydride vapor-phase epitaxy. Growth began as selective growth through openings in a SiO2 mask. Facets which consisted of {1¯1•1} planes were formed in the early stages, and a continuous film developed via coalescence of these facets on the SiO2 mask. As a result, GaN layers with dislocation densities as low as 6 x 107/cm2 were grown onto 5cm-diameter sapphire wafers. The GaN layers were crack-free and had a mirror-like surface.

A.Usui, H.Sunakawa, A.Sakai, A.A.Yamaguchi: Japanese Journal of Applied Physics - 2, 1997, 36[7B], L899-902