Backscattering analysis of ion bombardment damage in Nb and W at low (25degK) temperature

Abstract Bombardment-induced damage in single crystals of tungsten and niobium, implanted with 300-keV Ar+ at 25°K, has been examined by means of the channeling-effect technique. Target temperature was maintained at 25°K throughout the implantation and subsequent analysis in order to minimize annealing effects. Very high implantation doses (compared with doses involved in semiconductor work) had to be used before significant damage was observed. This would indicate that a strong spontaneous recovery occurs in these metals even at 25°K. The damage was seen mainly as an enhanced dechanneling component. In niobium a slight indication of a damage peak was also observed. Preliminary annealing studies did not show any significant annealing stages between 25°K and 300°K in the case of tungsten, while some annealing between 25°K and 300°K was observed in niobium.