View Publication | CEMHTI CNRS UPR3079 Orléans France

X.Kerbiriou, M.F.Barthe, A.Gentils, P.Desgardin, 'Thermal evolution of vacancy defects induced in 12 MeV H+ irradiated 6H-SiC single crystals', Physica Status Solidi C 4 3650-3653 (2007) doi:10.1002/pssc.200675796

In this work positron annihilation lifetime spectroscopy (PALS) has been used to investigate the evolution of the vacancy defects induced in 12 MeV H+ irradiated SiC as a function of the temperature. The irradiation has been performed at room temperature at a fluence of 4 x 1016 cm-2 in 6H-SiC single crystals using the CERI-Orléans cyclotron. Thermal treatments have been performed under an argon flux from 300 °C up to 1050°C. The positron lifetime has been measured as a function of the temperature in the range 15-600 K. After irradiation, positrons detect negative ions and two types of vacancy defects: VSi monovacancies and VSi-VC divacancies. After annealing, the lifetime behaviour as a function of the measurement temperature changes indicating different annealing stages. An increase of the long lifetime component is specially observed whereas the corresponding intensity decreases. These changes are correlated to the migration of VSi and the clustering with VSi-VC to form a new vacancy defect. The lifetime of this new defect has been determined and is equal to 235 ± 2 ps. We propose that it is related to VSi-VC-VSi.