Oxygen diffusion into SiO2-capped GaN during annealing

SiO2 layers were deposited on p-GaN (hole concentration 9 x 10(17) cm(-3)) by inductively coupled plasma chemical vapor deposition using an O-17-enriched O-2 precursor. The samples were then annealed at 500-900 degrees C and the SiO2 was removed. Secondary ion mass spectrometry profiling showed significant indiffusion of O-17 into the GaN under these conditions, with an incorporation depth of similar to 0.18 mu m after the 900 degrees C anneal. The O-17 diffusion profiles indicate that the high dislocation density in the GaN strongly affects the effective penetration depth. The GaN remained p type upon incorporation of the oxygen. (C) 1999 American Institute of Physics. [S0003-6951(99)00445-3].