Disorder accumulation and annealing on the Ga sub-lattice of material which had been implanted (60º from the surface normal) with 1MeV Au2+ at 180 or 300K were studied by using in situ Rutherford back-scattering spectrometry in an <00•1>-channelling geometry. Complete amorphization was obtained at 6 and 20 Au2+/nm2, for implantation at 180 and 300K, respectively. Saturation of Ga disorder at, and beyond, the damage peak was observed at intermediate ion fluences; at both 180 and 300K. No measurable thermal recovery was found, at 300K, for the full range of damage which was produced at 180K. Distinct epitaxial re-growth in the bulk, and Ga re-ordering at the surface, occurred upon annealing at 870K. The implanted Au diffused readily into the highly damaged regions at high temperatures, and the redistribution of Au atoms in the implanted material varied with the damage profile. A double-peak Au profile developed, with the maxima located in the amorphous surface region and near to the Au mean projected range. The results were explained in terms of Au diffusion into the amorphous regime near to the surface, and Au trapping at irradiation-induced defects in the crystalline material. The trapping effect was also reflected by a suppressed recovery of Au-decorated disorder.

In situ Ion Channelling Study of Gallium Disorder and Gold Profiles in Au-Implanted GaN W.Jiang, W.J.Weber, S.Thevuthasan: Journal of Applied Physics, 2000, 87[11], 7671-8