Electron-positron momentum distributions associated with vacancy defects in 6H-SiC after irradiation with 2MeV electrons and annealing at 1000C were studied using angular correlation of annihilation radiation measurements. It was confirmed that the above vacancy defects had dangling bonds along the c axis and the rotational symmetry around it. The first-principles calculation suggested that the vacancy defects were attributable to either C-vacancy-C-antisite complexes or Si-vacancy-N pairs, while isolated C vacancies, Si vacancies, and nearest neighbor divacancies were ruled out.

Angular Correlation of Annihilation Radiation Associated with Vacancy Defects in Electron-Irradiated 6H-SiC. A.Kawasuso, T.Chiba, T.Higuchi: Physical Review B, 2005, 71[19], 193204 (4pp)