Rutherford backscattering spectrometry channeling study of ion-irradiated 6H-SiC

Single-crystal 6H-SiC (α-SiC) wafers were irradiated with He+, C+ and Si+ ions to fluences ranging from 7.5×10 17 to 1×1020 ions m−2 at various temperatures (160–870 K). Damage accumulation and subsequent defect annealing (up to 1170 K) have been studied using in situ 2.0 MeV He+ Rutherford backscattering spectrometry combined with ion channeling (RBS/C) methods. The defect concentration at the damage peak is observed to increase sigmoidally with increasing ion fluence during irradiation at low temperatures. The isochronal recovery of irradiation damage induced at low temperatures is observed to follow an exponential dependence on temperature. The relative disorder accumulated under 550 keV C+ ion irradiation as a function of irradiation temperature exhibits a significant decrease between 300 K and 670 K. Irradiation with 550 keV Si+ at 180 K to a fluence of 6.0×1019 Si+ m−2 produces an amorphous layer extending from the surface to a depth of 0.6 μm. The thickness of this amorphous layer decreases linearly with annealing temperature up to 870 K. At low ion fluences, the defects produced by He+ irradiation at 160 K are more difficult to anneal at 300 K than those produced by Si+ irradiation, which suggests that trapping of helium may inhibit recombination.