Nature of Defects Induced by Au Implantation in Hexagonal Silicon Carbide Single Crystals

Pulsed-slow-positron-beam-based positron lifetime spectroscopy was used to investigate the nature of vacancy defects induced by 20 MeV Au implantation in single crystals 6H-SiC. Preliminary analysis of the data shows that at lower fluence, below 1014 cm-2, a positron lifetime of 220 ps has been obtained: it could be associated with the divacancy VSi-VC in comparison with the literature. At higher fluence, above 1015 cm-2, a positron lifetime of 260-270 ps, increasing with the incident positron energy, has been observed after decomposition of the lifetime spectra. By comparison with lifetime calculations, open-volumes such as quadrivacancy (VSi-VC)2 clusters could be associated with this value.