Reduction of Threading Dislocations in InGaN/GaN Double Heterostructure through the Introduction of Low-Temperature GaN Intermediate Layer

The reduction mechanism of threading dislocation at the interface of InGaN/low-temperature GaN (LT-GaN) layers was investigated by AFM, TEM, and SIMS measurements. Introducing the LT-GaN intermediate layer onto the InGaN active layer not only prevented In evaporation during the growth of the p-GaN layer but also suppressed the propagation of threading dislocations from InGaN to p-GaN. The propagation of threading dislocations is reduced by the formation of 2-D lateral islands, and further defect generation is prevented by the formation of InxGa1-xN alloy due to the relaxation of lattice mismatch between active InGaN and p-GaN. 12 refs.