Single crystals of 6H-type material were implanted with 1MeV He+ to a fluence of up to 2 x 1017/cm2 at room temperature. Rutherford back-scattering spectroscopy channelling analysis, using a 2MeV He+ beam, revealed the formation of extended defects or the generation of point defects, with a constant concentration over a depth of about 1. Electron microscopic characterization indicated the presence of 2 amorphous buried layers at depths of about 1.75 and 4.8. They were attributed to the implantation beam and to the Rutherford back-scattering spectroscopic analyzing beam, respectively. No extended planar or linear faults were found in the region between the surface and the first amorphous layer. However, a 50nm-thick amorphous layer was observed, at the surface, within which crystalline inclusions (apparently of diamond) were embedded. Such inclusions were also found in the crystalline material below the amorphous layer; but with a reduced number density.

N.Frangis, J.Van Landuyt, M.G.Grimaldi, L.Calcagno: Nuclear Instruments and Methods in Physics Research B, 1996, 120[1-4], 186-9