Avoiding pre-amorphization damage in MeV heavy ion-implanted silicon

Implantation of 1.0 MeV 115In in Si results in secondary‐defect formation during subsequent 900 °C annealing if the total number of displaced Si atoms is greater than 1.6×1017/cm2, achieved with a dose near 1.5×1013/cm2. We demonstrate, though, that higher total In doses can be introduced without forming secondary defects by repetitive subthreshold implants each followed by an anneal to remove the implant damage. While a single 6×1013 In/cm2implant results in a high density of dislocation loops after annealing, instead using four separate 1.5×1013 In/cm2 implants each followed by an anneal leads to the formation of only a few partial dislocations.