Thermal He desorption spectrometry was used to characterize He implantation-induced defects in SiC. 6H¯SiC and 4H¯SiC single crystals were implanted with He at energies ranging from 100eV to 3keV and doses ranging from 1013 to 1015/cm2. They were then subjected to ramp annealing up to 1800K, with a constant heating rate of 10K/s. To the desorption spectrum contribute 2 groups of peaks: one group at low temperature centered at 600K and another group at high temperature centered at 1200K. The evolution of these desorption peaks with implantation dose and energy was studied. The first group (at 600K) might be attributed to interstitial He and clusters of interstitial He. The second group (at 1200K) could be related to the de-trapping of He from He¯vacancy clusters. A shift of the latter group towards higher temperatures observed for increasing dose was ascribed to He¯vacancy clustering in an Ostwald ripening process.

Helium Implantation Defects in SiC Studied by Thermal Helium Desorption Spectrometry. E.Oliviero, A.van Veen, A.V.Fedorov, M.F.Beaufort, J.F.Barbot: Nuclear Instruments and Methods in Physics Research B, 2002, 186[1-4], 223-8