Helium implantation defects in SiC studied by thermal helium desorption spectrometry

Abstract

Thermal helium desorption spectrometry (THDS) was used to characterize helium implantation induced defects in SiC. 6H–SiC and 4H–SiC single crystals were implanted with helium at energies ranging from 100 eV to 3 keV and doses ranging from 10 13 to 10 15 cm −2 . They were then subjected to ramp annealing up to 1800 K, with a constant heating rate of 10 K s −1. To the desorption spectrum contribute two groups of peaks: one group at low temperature centered at 600 K and another group at high temperature centered at 1200 K. The evolution of these desorption peaks with implantation dose and energy has been studied. The first group (at 600 K) might be attributed to interstitial He and clusters of interstitial He. The second group (at 1200 K) could be related to the de-trapping of He from He–vacancies clusters. A shift of the latter group towards higher temperatures observed for increasing dose is ascribed to He–vacancy clustering in an Ostwald ripening process.