Defect characterization in electron-irradiated 6H-SiC by positron annihilation

Isochronal annealing investigations in electron-irradiated 6H-SiC were correlated with temperature dependent measurements of positron lifetime. It turned out that the positron trapping at temperatures up to 300 K was dominated by the trapping in shallow positron traps. These defects were already present in the unirradiated material and could be attributed to the antisite defects. The annealing of the irradiation-induced monovacancies and divacancies took a continuous course up to 1740 K. Ln the wide-temperature range between 300 and 1200 K, different monovacancylike defects annealed and above 1200 K the divacancy disappeared. The weak increase of the average positron lifetime between 750 and 1200 K detected at measurement temperatures below 300 K must be caused by partial annealing of shallow traps, probably irradiation-induced shallow traps. After the final annealing at 1740 K all of the irradiation-induced defects vanished. [S0163-1829(99)00516-0].