Optimum rapid thermal activation of Mg-doped p-type GaN

In this paper, we describe the electrical properties of Mg-doped GaN annealed using rapid thermal annealing. Metal-organic vapor phase epitaxy (MOVPE)-grown samples with Mg concentrations ranging from 1.25 x 10(19) to 1 x 10(20) cm(-3) were annealed at various temperatures in a nitrogen atmosphere. It was found that the maximum hole concentration achieved after rapid thermal annealing is limited to approximately 8 x 10(17) cm(-3) at room temperature and its optimum annealing temperature decreases with increasing Mg concentration. The temperature dependence of hole concentration suggested that the formation of donor complex defects is responsible for the suppressed electrical activation of Mg acceptors after annealing at high temperatures higher than the optimum annealing temperature.