Positron annihilation spectroscopy was used to investigate defects after electron irradiation of 6H n-type SiC. The density of vacancy-type defects strongly increased during the treatment. An isochronal annealing experiment was performed, and the main recovery stage was found to be between 1000 and 1400C. This corresponded to the annealing range of the E1/E2 defect, which was also found by a correlated positron and deep level transient spectroscopic study of 6H–SiC epilayers after electron irradiation. Optical excitation experiments performed during the positron experiment showed that the observed defect had an ionization level at about Ec-0.47eV; which was similar to the level of Ec-0.44eV obtained by deep level transient spectroscopy for the E1/E2 defect. Doppler-

coincidence experiments suggested that the observed vacancy was surrounded by C atoms, so that the Si vacancy (isolated or bound to an impurity or another defect) was most probably the predominant defect after electron irradiation.

Illumination Effects in Irradiated 6H n-Type SiC Observed by Positron Annihilation Spectroscopy. F.Redmann, A.Kawasuso, K.Petters, H.Itoh, R.Krause-Rehberg: Physica B, 2001, 308-310, 629-32