Positron annihilation lifetime spectroscopy was used to investigate the evolution of the vacancy defects induced in 12MeV H+ irradiated SiC as a function of temperature. The irradiation was performed at room temperature at a fluence of 4 x 1016/cm2 in 6H-SiC single crystals, using a cyclotron. Thermal treatments were performed, under an Ar flux, at 300C to 1050C. The positron lifetime was measured as a function of temperature at 15 to 600K. After irradiation, positrons detect negative ions and 2 types of vacancy defects: VSi monovacancies and VSi-VC divacancies. After annealing, the lifetime behaviour as a function of the measurement temperature changed; indicating different annealing stages. An increase of the long lifetime component was specially observed whereas the corresponding intensity decreased. These changes were correlated to the migration of VSi and the clustering with VSi-VC to form a new vacancy defect. The lifetime of this new defect was determined and was equal to 235ps. It was proposed that it was related to VSi-VC-VSi.Thermal Evolution of Vacancy Defects Induced in 12MeV H+ Irradiated 6H-SiC Single Crystals. X.Kerbiriou, M.F.Barthe, A.Gentils, P.Desgardin, Physica Status Solidi C, 2007, 4[10], 3650-3