Single crystals were implanted with 150keV Ar ions, at room temperature, to fluences that ranged from 5 x 1014 to 1016/cm2. The dose rate was about 1013/cm2s. Following implantation, the samples were isochronally annealed in vacuum at temperatures of up to 1000C. Before and after each annealing step, defect depth profiles were determined by means of -particle channelling, using a back-scattering geometry. The relative defect densities were deduced by extracting contributions, that were due to the Mg sub-lattice, from the normalized aligned spectra. These were then fitted to equations which described the de-channelling rate and the back-scattering yield as a function of depth. It was found that the defect density reached saturation at a fluence of 2 x 1015/cm3. Up to this dose, the damage profile was in agreement with computer predictions. At higher fluences, the thickness of the damaged region increased due to defect saturation of the tail region of the implantation profile. The experimental results confirmed the existence of a mixed damage structure which probably consisted of randomly disordered regions and extended defects. It was noted that annealing of the first defect component occurred at about 700C.

E.Friedland: Nuclear Instruments and Methods in Physics Research B, 1996, 116[1-4], 136-40