Single-crystal 6H-SiC wafers were bombarded with 50keV He+ ions, at 300K, to fluences ranging from 7.5 to 250/nm2. Ion-channelling experiments, using 2.0MeV He+ Rutherford back-scattering spectrometry, were used to determine the depth profile of Si disorder. The measured profiles were consistent with SRIM-97 simulations, at and below 45/nm2, but which were higher than the SRIM-97 prediction at both 100 and 150/nm2. Cross-sectional transmission electron microscopy indicated that the volume expansion of the material was not significant at intermediate damage levels. The results of elastic recoil detection analysis suggested that the implanted He atoms diffused in a high-damage regime towards the surface.

Disordering Behavior and Helium Diffusion in He+ Irradiated 6H-SiC. W.Jiang, W.J.Weber, C.M.Wang, Y.Zhang: Journal of Materials Research, 2002, 17[2], 271-4