Influence of substrate dopant concentration on electrical properties and residual defects in pn junction formed by low-temperature post-implantation annealing

Dependence of the leakage currents in BF2+ implanted junctions on the dopant concentration of the n-type substrate was investigated. It was clarified that the leakage currents of low-temperature-annealed junctions increase as the substrate dopant concentration increases, while high-temperature-annealed junctions have the opposite dependence. We demonstrate that low-leakage currents can be achieved in low-temperature-annealed junctions by using lightly doped silicon substrate. It was confirmed that the higher leakage currents in low-temperature-annealed junctions originate from the implantation-induced defects existing deeply in the substrate. Considering the results of both BF2+ implanted p+n junction and As+ implanted n+p junction, we discuss an implantation-induced defect generation mechanism.