Use of type II (end of range) damage as ‘‘detectors’’ for quantifying interstitial fluxes in ion-implanted silicon

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Abstract
Type-II (end of range) defects, produced by Ge+ implantation, were investigated as possible ‘‘detectors’’ for quantifying nonequilibrium interstitial concentrations following B+ implantation into silicon. The type-II damage was created with a 100 keV (1×1015/cm2) Ge+ implant into silicon followed by either a low-temperature (550 °C) or a high-temperature (800 °C) anneal. This resulted in the formation of either a layer of point-defect clusters and small (≤50 Å in diameter) dislocation loops or a layer of larger (∼160–400 Å in diameter) fully formed dislocations loops. This material was subsequently implanted with 30 keV B+ at doses between 7×1013/cm2 and 2×1014/cm2. After a final 800 °C anneal, the concentration of atoms bound by the type-II dislocation loops was measured. Results show that the concentration of interstitials bound by the type-II dislocation loops increases with increasing B+ dose. Relative to control sample values, the net concentration of interstitials trapped as a result of B+ implantation varied from 7.0×1013/cm2 to 1.8×1014/cm2 over the dose range studied. Fully formed loops were also found to be ≥20% more efficient than clusters in trapping the interstitials generated under identical B+ implant conditions. The difference is ascribed to the increase in equilibrium point-defect concentration necessary to stabilize the smaller loops prior to coarsening.