Defect reduction by MeV ion implantation for shallow junction formation

Abstract

p-type shallow junction formation requires residual defects reduction for ion implantation to suppress boron-enhanced diffusion. We have demonstrated that MeV ion implantation is effective to reduce end-of-range defects for shallow junction formation. F+ preimplantation was carried out at 40 keV with a dose of 1×1015 cm−2. B+ ions were implanted at 10 keV with a dose of 5×1015 cm−2 in the F+-preimplanted samples, followed by 1 MeV F+, Si+, or 2 MeV As+ implantation at substrate temperatures of room temperature and 400 °C with doses ranging from 5×1014 to 5×1015 cm−2. Annealing was carried out by rapid thermal annealing at 1000–1100 °C for 10 s. F+ preimplantation induced shallower junction formation, however, much reduction of the junction depth was observed by 1 MeV F+ or Si+ implantation, because of end-of-range defects reduction for the suppression of boron-enhanced diffusion. About a 50% shallower junction depth was obtained by F+ preimplantation, followed by 1 MeV F+ or Si+ implantation, when this junction was compared with just B+-implanted samples.