Behaviors of vacancy-type defects in Mg-implanted GaN during ultra-high-pressure annealing studied by using a monoenergetic positron beam

Vacancies in Mg-implanted GaN were probed using positron annihilation technique. Mg was implanted into GaN with [Mg] = 1E19 /cm3. For an as-implanted sample, the major defect species was identified as Ga-vacancy related defects. The sample was annealed under a nitrogen pressure of 1 GPa in a temperature range of 1000–1480C without a protective capping layer. Comparing with the sample annealed with the capping layer, although no large difference in the defect spices was observed, their concentration was decreased by the cap-less annealing. The diffusion of Mg during annealing was influenced by the presence of residual vacancies. H was unintentionally incorporated into the sample during annealing, and its diffusion property were also affected by vacancies and Mg. A part of this work was supported by MEXT “Research and development of next-generation semiconductor to realize energy-saving society (JPJ005357)” and the Polish National Science Centre through project No 2018/29/B/ST5/00338.