Quantification of Excess Vacancy Defects From High-Energy Ion Implantation in Si by Au Labeling

It has been shown recently that Au labeling (V.C. Venezia et al., Appl. Phys. Lett. 73, 2980, 1998) can be used to profile vacancy- type defects located near half the projected range (1/2 Rp) in MeV-implanted Si. In this letter we have determined the ratio of vacancies annihilated to Au atoms trapped (calibration factor "k") for the Au labeling technique. The calibration experiment consisted of three steps: 1) a 2-MeV Si sup + implant into Si(100) followed by annealing at 850C to form stable excess vacancy defects; 2) controlled injection of interstitials in the 1/2 Rp region of the above implant via 600-keV Si sup + ions followed by annealing to dissolve the {311} defects; and 3) Au labeling. The reduction in Au concentration in the near surface region (0.1-1.6 microns) with increasing interstitial injection provides the most direct evidence so far that Au labeling detects the vacancy- type defects. By correlating this reduction in Au with the known number of interstitials injected, it was determined that k=1.2+0.2 vacancies per trapped Au atom.