Layers of SiO2 were deposited onto p-type GaN by means of inductively coupled plasma chemical vapour deposition, using 17O-enriched O2 precursor. The samples were then annealed at 500 to 900C, and the SiO2 was removed. Secondary ion mass spectrometry profiling revealed significant in-diffusion of 17O under these conditions (figure 6), with an incorporation depth of about 0.18μm after annealing at 900C. The 17O diffusion profiles indicated that the high dislocation density in the material strongly affected the penetration depth.

Oxygen Diffusion into SiO2-Capped GaN during Annealing S.J.Pearton, H.Cho, J.R.LaRoche, F.Ren, R.G.Wilson, J.W.Lee: Applied Physics Letters, 1999, 75[19], 2939-41