A transmission electron microscopic study was made of the mechanisms of defect reduction in metal-organic vapour phase epitaxial growth on a sapphire substrate. The first growth step involved the bending of dislocations and thus led to a sharp reduction in the density of vertically threading defects. In a second step, the dislocations maintained their line in the basal plane and propagated horizontally towards the coalescence boundary with GaN coming from adjacent windows. Plan-view observations revealed that large areas were free from dislocations at the transmission electron microscopic scale.

TEM Study of the Behavior of Dislocations during ELO of GaN V.Bousquet, P.Vennéguès, B.Beaumont, M.Vaille, P.Gibart: Physica Status Solidi B, 1999, 216[1], 691-5