Abstract
Characterization of dominant electron trap in as-grown SiC epilayers has been carried out using deep level transient spectroscopy. Two electron traps
E
1
and
Z
1
at
E
c
−
0.21
and
E
c
−
0.61
are observed, respectively;
Z
1
being the dominant level. Line shape fitting, capture cross section, and insensitivity with doping concentration have revealed interesting features of
Z
1
center. Spatial distribution discloses that the level is generated in the vicinity of epilayers∕substrate interface and the rest of the overgrown layers is defect-free. Owing to the Si-rich growth conditions, the depth profile of
Z
1
relates it to carbon vacancy. The alpha particle irradiation transforms
Z
1
level into
Z
1
∕
Z
2
center involving silicon and carbon vacancies. Isochronal annealing study further strengthens the proposed origin of the debated level.