Annealing behavior of vacancies and Z(1/2) levels in electron-irradiated 4H-SiC studied by positron annihilation and deep-level transient spectroscopy

Annealing behavior of vacancies and the Z(1/2) levels in n-type 4H-SiC epil ayers after 2 MeV electron irradiation has been studied using positron anni hilation and deep-level transient spectroscopy. Isochronal annealing studie s indicate that silicon vacancy-related defects are primarily responsible f or positron trapping. The Z(1/2) levels are the predominant deep centers af ter irradiation and subsequent annealing at 1200 degreesC. Both the positro n-trapping rate at vacancies and the Z(1/2) concentration decrease in a sim ilar manner while annealing from 1200 to 1500 degreesC. It is thus proposed that the Z(1/2) levels originate from silicon vacancy-related defects. (C) 2001 American Institute of Physics.