Helium implantation defects in SiC: A thermal helium desorption spectrometry investigation

Abstract

Thermal helium desorption spectrometry was used to characterized helium implantation-induced defects in SiC. 6H–SiC, 4H–SiC, and β–SiC samples were implanted with helium at energies ranging from 100 to 3 keV and doses ranging from 1×1013 to 1×1015 cm−2. They were then subjected to ramp annealing up to 1800 K, with a constant heating rate of 10 K/s. Two groups of peaks contribute to the desorption spectrum: A low-temperature group centered at 600 K and a high-temperature group centered at 1200 K. The evolution of these desorption peaks with implantation dose and energy was 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 He release from He-vacancy clusters. A shift of the latter group toward higher temperatures with increasing dose is ascribed to He-vacancy clustering in an Ostwald ripening process. However, the intrinsic properties of the materials used in the study seem to play an important role since different detrapping behaviors were observed for the different samples.