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 x 10(14) 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 degrees C and all the Hf ions then occupy substitutional sites. The hyperfine interaction measurements were performed with the radioactive Hf-181/Ta-181 probe, after implantation of Hf-181 to a fluence of 5 x 10(12) Hf+ cm(-2) with 80 keV. These measurements show that the defect recovery occurs in the 600-800 degrees C annealing temperature range. (C) 1999 Elsevier Science S.A. All rights reserved.