Vacancy‐type defects and their annealing behaviors in Mg‐implanted GaN studied by a monoenergetic positron beam

Abstract

Vacancy‐type defects in Mg‐implanted GaN were probed using a monoenergetic positron beam. Mg ions of multiple energies (15–180 keV) were implanted to provide a 200‐nm‐deep box profile with Mg concentration of 4 × 1019 cm−3. The major defect species of vacancies introduced by Mg‐implantation was a complex between Ga‐vacancy (VGa) and nitrogen vacancies (VNs). After annealing above 1000 °C, these defects started to agglomerate, and the major defect species became (VGa)2 coupled with VNs. The defect reaction occurred between not only the defects introduced by the implantation but also the defects introduced by an excess Mg‐doping. The depth distribution of vacancy‐type defects agreed well with that of implanted Mg, and no large change in the distribution was observed up to 1300°C annealing. Relationships between photoluminescence bands and vacancy‐type defects introduced by Mg‐implantation are also discussed.