The annealing of damage in 6H-type material, which was caused by ion implantation to 2 different fluences, was studied by using mono-energetic positron Doppler broadening and lifetime techniques. The measurements were supported by calculations of the positron lifetimes in vacancy clusters. At both fluences, 2 defective layers were identified and characterized, by depth and defect-type, as a function of the annealing temperature. The results indicated that it was impossible to remove the radiation damage by annealing at temperatures of up to 1500C.

G.Brauer, W.Anwand, P.G.Coleman, J.Störmer, F.Plazaola, J.M.Campillo, Y.Pacaud, W.Skorupa: Journal of Physics - Condensed Matter, 1998, 10[5], 1147-56