Layers of SiO2 were deposited onto p-type GaN by means of inductively coupled plasma chemical vapor deposition, using a 17O-enriched O precursor. The samples were then annealed at 500 to 900C (figure 1), and the SiO2 was removed. Secondary ion mass spectrometry profiling revealed a significant in-diffusion of 17O into the GaN under these conditions, with an incorporation depth of about 0.18μm after the 900C annealing. The 17O diffusion profiles indicated that the high dislocation density in the GaN strongly affected the effective penetration depth. The GaN remained p-type after O incorporation.

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

Figure 1

Diffusivity of 17O in GaN