Vacancy defects in high-quality 4H and 6H SiC epilayers induced by electron irradiation have been characterized using positron annihilation and deep level transient spectroscopy (DLTS). Vacancy defects were annealed in two steps below 700°C and above 1200°C irrespective to polytype. From the correlation between positron annihilation and DLTS data using the same wafers, it was confirmed that complexes including silicon vacancies are the origin of the E1/2 levels in 6H SiC and the Z1/2 level in 4H... »