ELECTRICAL AND STRUCTURAL CHARACTERIZATION OF BF2+ SELF-ANNEALED IMPLANTATION

Silicon wafers, (100) oriented, were implanted with BF; at a dose of 1 x 1015 cm-2, at constant dose rate and different implantation energies between 100 and 350 keV, to change the power density between 0.2 and 0.7 W/cm2. Under these conditions the maximum temperature reached by the samples at the highest power density was calculated to be 590 K. In order to study the mechanism for dynamic annealing, which is active in these experimental conditions, electrical measurements, RBS-channeling, TEM and SIMS analyses were performed. The process of recovery of the implantation damage shows a well defined threshold between 0.45 and 0.50 W/cm2, however, only after a prolonged thermal treatment the implanted boron becomes electrically active, presumably in connection with fluorine diffusion.