Ion beam induced strain relaxation in pseudomorphous epitaxial SiGe layers

The effects of irradiation with Ge/sup +/ and Ar/sup +/ ions at elevated temperatures on the relaxation behavior of pseudomorphic Si/sub 0.79/Ge/sub 0.21//Si heterostructures have been compared. It was found the strain relaxation in the structures implanted with Ge/sup +/ at 400/spl deg/C started already upon implantation, post-implantation thermal annealing of this sample resulted in considerably higher degree of relaxation than that in control (non-implanted) samples as well as in samples implanted with Ar/sup +/ both at 230 and 4000/spl deg/C and with Ge/sup +/ at 230/spl deg/C. This result points to a dramatic influence of both the implantation temperature and ion species on relaxation behavior of the ion-irradiated heterostructure. Two possible mechanisms for this effect are discussed.