LATTICE DISORDER PRODUCED IN Si BY 40-keV BORON AND ITS EFFECT ON ELECTRICAL BEHAVIOR

Abstract

The lattice disorder produced by 40 keV boron ions in Si at implant temperatures of −120 and 23°C has been measured by means of the channeling technique for a 140‐keV proton beam. At −120° there are ∼ 650 displaced Si atoms per incident boron ion for random and 〈111〉 aligned implants, respectively. In contrast to the mild dependence noted earlier for Sb implants, there is a marked dependence of residual lattice disorder upon implant temperature for boron implants in this temerature range. Hall effect measurements on the implanted layers indicate that, in the dose range for boron investigated here, the electrical yield (number of acceptors per implanted ion) after a 600°C anneal increases with the amount of disorder contained in the implanted layer, with the greatest yield occurring in implants containing a fully amorphous layer. The major effect of implant temperature is to determine the amount of residual disorder.