The properties of samples which had been damaged by 180keV Zn ions were studied, after ion doses which ranged from 1013 to 1016/cm2, by using ion-channelling techniques. It was found that the material could not be made amorphous by implantation at room temperature, or liquid N temperatures, at the doses that were investigated. When the ion dose was less than 1014/cm2, samples which had been implanted at liquid N temperatures experienced less damage than that did samples which had been implanted at room temperature. The difference could amount to an order of magnitude. Moreover, no simple point defects or amorphous clusters were found in the implanted material. After doses of more than 1014/cm2, the samples were still monocrystalline but became highly defective; with extended defects. The results suggested that point defects which were created during implantation could be mobile at, or below, room temperature and could migrate rapidly under ion bombardment.

K.M.Yu, E.D.Bourret-Courchesne: Applied Physics Letters, 1996, 69[14], 2062-4