Pressure Effect on Diffusion of Native Defects and Mg Impurity in Mg-Ion-Implanted GaN during Ultrahigh-Pressure Annealing

Herein, transmission electron microscopy direct observations are used to examine the time evolution of dislocation loops in Mg-ion-implanted GaN during annealing in N-2 atmospheres of 2.0 and 0.3 GPa. It is indicated in the results that the diffusion of the native defects, for both interstitials and vacancies, is retarded during annealing at the higher pressure. Furthermore, secondary ion mass spectrometry shows that annealing at the higher pressure retards the migration of Mg and increases Mg-acceptor concentration in the ion-implanted region. These findings provide a design principle of the postimplantation annealing process to activate ion-implanted Mg in GaN.