Defect recovery was studied in Er-implanted epilayers which had been grown onto sapphire. The samples were investigated after annealing at 1000C, with a proximity cap, and at 1200C under high-pressure (1GPa) N. Room-temperature implantation of 160keV Er ions was carried out using nominal fluences of 5 x 1014 or 5 x 1015/cm3. Some samples were co-implanted with O ions. During implantation to lower doses, a large fraction of the Er was incorporated at Ga sites. The implantation damage recovered almost completely after rapid thermal annealing (1000C, 120s, proximity cap). Such annealing had no effect upon the Er profile. An increase in annealing time led to degradation of the surface, due to N loss. Samples which were implanted to higher fluences, and were subjected to the same annealing procedure, exhibited differing behaviours; depending upon the presence of O. In the case of samples without O, recovery was faster and was accompanied by the segregation of Er towards the surface. In the case of samples which contained O, damage recovery proceeded slowly and the Er profile remained stable. Annealing at 1200C in N, at a pressure of 1GPa, promoted complete recovery of the damage in samples without O.

High-Temperature Annealing of Er-Implanted GaN. E.Alves, T.Monteiro, J.Soares, L.Santos, M.F.Da Silva, J.C.Soares, W.Lojkowski, D.Kolesnikov, R.Vianden, J.G.Correia: Materials Science and Engineering B, 2001, 81[1-3], 132-5