Defect Elimination by MeV Ion Implantation

Abstract

ABSTRACTIn the p-type shallow junction formation using B+ implantation, preamorphaization is an essential technique to suppress B+ channeling. The crucial problem in this process is defect formation at an amorphous-crystal(a-c) interface. We have demonstrated that MeV ion implantation is effective to reduce defects for shallow junction formation. F+ preimplantation at 40 KeV with 1×l015 cm−2 was effective to form p-type shallow junctions by B+ implantation at 10 KeV with 5×1015cm−2. However, defect formation induced boron diffusion and also leakage current increase. These problems were overcome by MeV ion implantation at 1 MeV F+ or Si+ with 5x×1015 cm−2, followed by rapid thermal annealing at 1000–1100°C for 10 seconds. In the P preimplanted samples, followed by MeV ion implantation, defects at the a-c interface can be reduced and an about 50 % shallower junction depth was obtained, compared with just B+ implanted samples. The results indicate that MeV ion implantation is effective to form a shallow junction with a low leakage current.