Electron-positron momentum distributions associated with vacancy defects in 6H-SiC after irradiation with 2MeV electrons and annealing (1000C) were studied by using angular correlation of annihilation radiation measurements. It was confirmed that the above vacancy defects have 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-nitrogen 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)