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

Abstract

Annealing behavior of vacancies and the $Z_{\text{1/2}}$ 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 $Z_{\text{1/2}}$ levels are the predominant deep centers after irradiation and subsequent annealing at $\text{1200\hspace{0.05em}°}\mathrm{C}.$ Both the positron-trapping rate at vacancies and the $Z_{\text{1/2}}$ concentration decrease in a similar manner while annealing from 1200 to $\text{1500\hspace{0.05em}°}\mathrm{C}.$ It is thus proposed that the $Z_{\text{1/2}}$ levels originate from silicon vacancy-related defects.