Vacancy‐Type Defects in n‐Type GaN Fabricated by Low‐Dose Ion Implantation Studied by a Monoenergetic Positron Beam

Annealing behaviors of vacancy‐type defects in low‐dose ion‐implanted GaN are studied by positron annihilation. N + , Al + , and Si + ions are implanted with a dose of 1 × 10 12 cm −2 . For Al‐ and Si‐implanted GaN after annealing at 1100 °C, the depth profiles of the net donor concentration ( N D ) are close to those for implanted impurities, but N D is 2–3 times higher than Al or Si concentrations. N D of N‐implanted GaN is higher than that of an unimplanted sample but is lower than that of the Al‐ and Si‐implanted samples. The origin of donor‐like defects introduced by ion implantation is expected to be N‐vacancy‐related defects. A comparison between depth profiles of vacancy‐type defects and N D reveals that Ga‐vacancy (V Ga )‐type defects play a significant role in the annealing behavior of N D . Photoexcitation of V Ga ‐type defects and their electron detrapping phenomena are also studied.