Annealing behavior of vacancies and the Z1/2 levels in n-type 4H–SiC epilayers after 2MeV electron irradiation was studied using positron annihilation and deep-level transient spectroscopy. Isochronal annealing studies indicate that Si vacancy-related defects were primarily responsible for positron trapping. The Z1/2 levels were the predominant deep centers after irradiation and subsequent annealing at 1200C. Both the positron-trapping rate at vacancies and the Z1/2 concentration decrease in a similar manner while annealing from 1200 to 1500C. It was thus proposed that the Z1/2 levels originated from Si vacancy-related defects.

Annealing Behavior of Vacancies and Z1/2 Levels in Electron-Irradiated 4H–SiC Studied by Positron Annihilation and Deep-Level Transient Spectroscopy. A.Kawasuso, F.Redmann, R.Krause-Rehberg, M.Weidner, T.Frank, G.Pensl, P.Sperr, W.Triftshäuser, H.Itoh: Applied Physics Letters, 2001, 79[24], 3950-2