X-ray diffraction studies of radiation damage in gallium arsenide

Abstract X-ray diffraction was used to study the damage caused by ion implantations in gallium arsenide. The dependence of damage induced strain (DIS) on various implantation parameters was investigated. It was found that the amount of DIS increases with ion mass, dose and dose rate, while it decreases with substrate temperature. The thickness of the damaged layer was found to depend approximately linearly on implantation energy. Results obtained from these studies were used to interpret the annealing behaviour of n-type impurities (sulphur and selenium) in GaAs. After implantation these elements showed upon annealing an activation energy which decreased with increasing implantation temperature. As the annealing may be considered to consist of regrowth of the damaged layer and activation of the impurities, the activation energies obtained from annealing experiments should reflect these two processes. This means that the activation energies found may vary for different experimental conditions. This should be generally valid for compound semiconductors.