Annealing behavior of vacancies and $Z1/2$ levels in electron-irradiated 4H–SiC studied by positron annihilation and deep-level transient spectroscopy

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