Positron annihilation study of vacancy-type defects in silicon carbide co-implanted with aluminum and carbon ions

Co-implantation of Al (2×10¹⁸/cm^-3) and C (1×10¹⁸/cm^-3), Al/C, into 6H-SiC and subsequent annealing up to 1650°C were performed. Vacancy-type defects in the implanted layers were studied by positron annihilation spectroscopy. The mean size of vacancy-type defects produced by Al/C-implantation is found to be close to the size of divacancy. The mean size of vacancy-type defects is hardly changed by annealing below 600°C, and vacancy clustering occurs in an annealing temperature range between 600°C and 1000°C. At annealing temperatures between 1000°C and 1400°C, the mean size of vacancy-type defects decreases, and the major vacancy defects are annealed out above 1400°C. No significant difference is observed in the annealing behavior of vacancy-type defects between samples implanted with Al/C and only Al.