Recovery of dry-etch-induced surface damage on Mg-doped GaN by NH3 ambient thermal annealing

We report that NH3 ambient thermal annealing is a promising method for recovering the dry- etch-induced damage on Mg-doped GaN surfaces. The surface electrical properties of dry-etched Mg-doped GaN can be fully recovered by thermal annealing using NH3 as an ambient gas at temperatures above 900 °C. The complete recovery of sheet hole concentration in dry-etched Mg-doped GaN can be attributed to a reduction in excess nitrogen vacancies in the damaged surface region by reactive nitrogen atoms supplied during NH3 ambient thermal annealing.