The lattice-site location of Hf which had been implanted into GaN monocrystalline epilayers were studied by combining Rutherford back-scattering spectroscopy/channelling and hyperfine interaction measurements. Those which were performed after implanting 100keV Hf+ ions, to a dose of 5 x 1014/cm2, showed that nearly all of the implanted ions were incorporated at substitutional sites. The damage which was produced by implantation recovered almost completely after annealing (900C, 1h), and all of the Hf ions then occupied substitutional sites. Hyperfine interaction measurements were performed using radioactive 181Hf/181Ta probes, after implanting 80keV 181Hf to a fluence of 5 x 1012/cm2. The measurements showed that defect recovery occurred during annealing at 600 to 800C.

Annealing Behavior and Lattice Site Location of Hf Implanted GaN. E.Alves, M.F.Da Silva, J.G.Marques, J.C.Soares, K.Freitag: Materials Science and Engineering B, 1999, 59[1-3], 207-10