HREM study of basal stacking faults in GaN layers grown over sapphire substrate

Inside GaN layers grown over (0001) sapphire by metal-organic chemical vapor deposition, we have analysed the three stacking faults of the structure: the two intrinsic faults I1 and I2 (with vectors equal to 1/6 20−23 and 1/3 10−10, respectively) and the extrinsic fault E (b=1/2 [0001]). A sequence of the three faults I1, I2 and E was observed near the interface with the substrate as well as the switch from one configuration to another.