The lateral extension of radiation damage in ion-implanted semiconductors

Implantation into a confined surface area produces considerable radiation damage even outside the implanted area. The distance between the damage boundary and the implantation boundary can be determined by simultaneously recording the sample current and the characteristic x-ray signal in a scanning electron microscope. This method was applied to investigate the lateral extent of radiation damage in Si, GaAs, and GaP. Annealing studies were performed with Si. It was found that the lateral excess of damage over the implanted area can be more than 1 μm even if the projected range is less than 0.1 μm. In Si, this marginal damage, except for oxidation induced stacking faults, can be annealed under the same conditions as necessary for the annealing of the implanted zone itself. Experimental support is given to the prediction of Campisano and Barbarino [1] that within the implanted region the recrystallization rate of the amorphous layer reaches a maximum within a range of concentration near the maximal solid solubility.