Rutherford back-scattering spectroscopy/channelling were used in situ to investigate damage accumulation and annealing in monocrystalline wafers of 6H-type material which had been bombarded with 390keV He+ ions, at temperatures of between 160 and 300K, to fluences ranging from 7.5 x 1018 to 1020/m2. Damage recovery was studied by performing isochronal annealing at temperatures of up to 1170K. The results showed that complete amorphization did not occur, at 190K, for fluences of up to 1020/m2 (0.38dpa at the damage peak). After a fluence of 4.5 x 1019/m2, the relative amount of damage which accumulated during bombardment at 190K was a factor of 5 greater than that which accumulated during bombardment at 300K. This suggested a higher rate of simultaneous point defect recombination at 300K. In post-bombardment isochronal annealing studies, the integrated damage profile for all of the bombarded samples decreased exponentially with increasing annealing temperature. For low relative fluences and comparable bombardment-induced defect concentrations, the defects which were produced by He+ bombardment at 160K were more difficult to anneal out at 300K than were those which were produced by Si+ bombardment at 160K. It was concluded that trapping of the He atoms at defects could have been inhibiting recombination.

Accumulation and Recovery of Irradiation Damage in He+ Implanted α-SiC. W.Jiang, W.J.Weber, S.Thevuthasan, D.E.McCready: Journal of Nuclear Materials, 1998, 257[3], 295-302