Isochronal annealing investigations of electron-irradiated 6H-type material were correlated with temperature-dependent measurements of positron lifetimes. Positron trapping at temperatures of up to 300K was dominated by trapping in shallow positron traps. These defects were already present in non-irradiated samples, and were attributed to antisite defects. Annealing of irradiation-induced monovacancies and divacancies was continuous up to 1740K. At temperatures ranging from 300 to 1200K, various monovacancy-like defects annealed out and, above 1200K, the divacancy disappeared. A slight increase in the average positron lifetime between 750 and 1200K, as detected at measurement temperatures below 300K, was attributed to partial annealing of shallow traps. These were probably irradiation-induced shallow traps. After final annealing at 1740K, all of the irradiation-induced defects vanished.

Defect Characterization in Electron-Irradiated 6H-SiC by Positron Annihilation. A.Polity, S.Huth, M.Lausmann: Physical Review B, 1999, 59[16], 10603-6