Oxygen diffusion into SiO2-capped GaN during annealing

SiO 2 layers were deposited on p-GaN (hole concentration 9×1017 cm−3) by inductively coupled plasma chemical vapor deposition using an O17-enriched O2 precursor. The samples were then annealed at 500–900 °C and the SiO2 was removed. Secondary ion mass spectrometry profiling showed significant indiffusion of O17 into the GaN under these conditions, with an incorporation depth of ∼0.18 μm after the 900 °C anneal. The O17 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.