Direct observation of formation of threading dislocations from stacking faults in GaN layer grown on (0 0 0 1) sapphire

We report direct observation of the formation of threading dislocations from stacking faults in GaN layers grown on (0 0 0 1) sapphire by hydride vapor phase epitaxy. High-resolution electron microscopy revealed that the stacking sequence of the stacking fault is “AaBbCcBbAa” and threading dislocations are generated from Shockley partials bounding the stacking fault. A model is proposed to explain how such stacking faults lead to the generation of threading dislocations.