Comparison of boron diffusion in silicon during shallow p+/n junction formation by non‐melt excimer and green laser annealing

Abstract

AbstractThe combination of Ge pre‐amorphization implantation, low‐energy boron implantation, and non‐melt laser annealing is a promising method for forming ultrashallow p+/n junctions in silicon. In this study, shallow p+/n junctions were formed by non‐melt annealing implanted samples using a green laser (visible laser). The dopant diffusion, activation, and recrystallization of an amorphous silicon layer were compared with those obtained in our previous study in which non‐melt annealing was performed using a KrF excimer laser (UV laser). The experimental results reveal that only slight diffusion of boron in the tail region occurred in green‐laser‐annealed samples. In contrast, remarkable boron diffusion occurred in KrF‐laser‐annealed samples for very short annealing times. Recrystallization of the amorphous silicon layer was slower in green‐laser‐annealed samples than in KrF‐laser‐annealed samples. We consider the penetration depth and the pulse duration are important factors that may affect boron diffusion.