Using density-functional total energy calculations, an investigation was made of N interstitial migration in GaN. Two migration paths were considered. The first path confined motion to a single c-plane of the lattice, while the second path involved movement both perpendicular and parallel to the c-axis. The latter path had a lower barrier for the positive charge states and would be the predominant mechanism for migration of the N interstitial in p-type GaN. The calculated barriers were 1.79, 2.12, and 1.98eV for the +1, +2, and +3 charge states. These barriers were consistent with recent experimental results and indicated that interstitials would be mobile at typical processing temperatures.

Density Functional Theory Investigation of N Interstitial Migration in GaN. R.R.Wixom, A.F.Wright: Journal of Applied Physics, 2006, 100[12], 123108