By eliminating metal contamination caused by sputtering events occurring behind the wafer as well as in front of the wafer, we have successfully formed ultrashallow, low-reverse-bias-current n(+)p junctions by postimplantation annealing conducted at a temperature as low as 450 degrees C. Further, we propose that the increased leakage current still present in the absence of metallic contamination is due to the residual damage which is the ion-implantation generated point defects widely distributed in the bulk of silicon. Effects of each point defect becomes more pronounced as the annealing temperature is reduced.