USE OF TYPE-II (END OF RANGE) DAMAGE AS DETECTORS FOR QUANTIFYING INTERSTITIAL FLUXES IN ION-IMPLANTED SILICON

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 X 10(15)/cm2) Ge+ implant into silicon followed by either a low-temperature (550-degrees-C) or a high-temperature (800-degrees-C) anneal. This resulted in the formation of either a layer of point-defect clusters and small (<50 angstrom in diameter) dislocation loops or a layer of larger (approximately 160-400 angstrom in diameter) fully formed dislocations loops. This material was subsequently implanted with 30 keV B+ at doses between 7 X 10(13)/cm2 and 2 X 10(14)/cm2. After a final 800-degrees-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 X 10(13)/cm2 to 1.8 X 10(14)/cm2 over the dose range studied. Fully formed loops were also found to be greater-than-or-equal-to 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.