The effect of implant energy, dose, and dynamic annealing on end-of-range damage in Ge+-implanted silicon

Abstract

A study of the effect of Ge+ implantation energy, dose, and temperature on the concentration of atoms bound by the extrinsic end-of-range dislocation loops in Si 〈100〉 wafers is presented. Plan-view and cross-sectional transmission electron microscopy observations of both the as-implanted and annealed (900 °C, 30 min) morphology were made. The implant energy was varied from 30 to 150 keV, the dose varied from 2×1014 to 1×1016/cm2, and the temperature was varied by using three different wafer-cooling methods during the implantation. Increasing the implant energy, dose, or wafer temperature all resulted in significant increases (as much as two orders of magnitude) in the concentration of atoms bound by the end-of-range loops. Recent models have suggested that the concentration of end-of-range defects is related to the integrated recoil concentration beyond the amorphous/crystalline (a/c) interface. Correlation of trim-88 calculations with measured a/c depths show that the integrated recoil concentration beyond the a/c interface can explain both qualitatively and quantitatively the dependence of the ‘‘trapped interstitials’’ on the implant energy. However, this model can only qualitatively explain the temperature dependence of the defects, and it fails to account for the strong dose dependence when wafer heating is suppressed.