Dose rate and orientation dependence of damage induced by Xe and Cd implants in InSb

The radiation damage caused by the implantation of 300 keV Xe and Cd ions into InSb was measured by means of the channeling technique using an 800 keV 4He beam. The disorder caused by room temperature implantations was measured as a function of (a) the implantation dose, (b) the implantation dose rate, and (c) the implantation direction with respect to the crystal axis. It was found that the damage in InSb reaches the random level at doses which depend on the implantation conditions. The fact that the 'amorphous' level could be reached as a result of heavy ion implantation into InSb fits well with the monotonic dependence of the damage-saturation on ionicity observed for other semiconductors. A previous discrepancy with the ionicity model which existed for InSb damaged with Bi ions is thus removed. Low dose rate (4 nA/cm2) implantations and implantations along a major crystalline axis (<111>) were found to cause less damage with different profiles than did high dose (40 nA/cm2) or random direction implantations, indicating that the mechanisms responsible for the creation of the stable damage complexes depend on the implantation conditions. While the damage seems to increase linearly with the dose for the high flux implantation, its dependence on the dose for low flux implantation seems to increase only as the square root of the dose, in agreement with Chadderton's model (Rad. Effects; 8:77 (1971)) which assumes different damage nucleation processes for different dose rates. (author)