Annealing behavior and lattice site location of Hf implanted GaN

The defect recovery and lattice site location of Hf implanted into GaN single crystalline epilayers were studied combining RBS/channelling and hyperfine interactions measurements. The RBS/channelling measurements performed after implantation of 5×1014 Hf+ cm−2 at 100 keV show that nearly all the implanted ions were incorporated into substitutional sites of the GaN lattice. The damage produced by the implantation recovers almost completely after one hour annealing at 900°C and all the Hf ions then occupy substitutional sites. The hyperfine interaction measurements were performed with the radioactive 181Hf/181Ta probe, after implantation of 181Hf to a fluence of 5×1012 Hf+ cm−2 with 80 keV. These measurements show that the defect recovery occurs in the 600–800°C annealing temperature range.