< 0001 > channeling stopping power of MeV He+ ions in 4H-and 6H-SiC

4H-SiC and 6H-SiC thin films as top surface layers of SiCOI wafers and Rutherford Back Scattering experiments with He+ ions in the energy range 0.9 - 2.2 MeV were used for measuring the He+ ions <0001> channeling stopping power with respect to the SiC random one. The film thicknesses were in the range 270-360 nm. The ratio between axial and random stopping power values decreased for increasing energy values and was higher for the 6H polytype with respect to the 4H one, i.e. it ranged from 0.85 to 0.72 for the former and from 0.80 to 0.66 for the latter.