Thermal He desorption spectrometry was used to characterize He implantation-induced defects. Single crystals of 6H–SiC and 4H–SiC material 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 at up to 1800K, with a constant heating rate of 10K/s. Two groups of peaks contributed to the desorption spectrum: one group at low temperatures was centered at 600K and another group at high temperatures was centered at 1200K. The evolution of these desorption peaks with implantation dose and energy was studied. The first group (at 600K) could 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 in the latter group, towards higher temperatures with increasing dose, was attributed to He–vacancy clustering via 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 Section B, 2002, 186[1-4], 223-8