The reduction mechanism of threading dislocations at the interface of InGaN/low-temperature GaN layers was investigated by means of atomic force microscopic,

transmission electron microscopic and secondary ion mass spectroscopic measurements. It was found that adding the low-temperature GaN intermediate layer to the InGaN active layer not only prevented In evaporation during growth of the p-type GaN layer but also suppressed the propagation of threading dislocations from InGaN to p-type GaN. The propagation of threading dislocations was reduced by the formation of 2-dimensional lateral islands, and further defect generation was prevented by the formation of InxGa1-xN; due to the relaxation of lattice mismatch between active InGaN and p-type GaN.

Reduction of Threading Dislocations in InGaN/GaN Double Heterostructure through the Introduction of Low-Temperature GaN Intermediate Layer. D.H.Yoon, K.S.Lee, J.B.Yoo, T.Y.Seong: Japanese Journal of Applied Physics - 1, 2002, 41[3A], 1253-8