Comparison of Boron Diffusion in Silicon during the Formation of Shallow p+/n Junction with KrF and Green Laser Annealing

Abstract

A combination of Ge pre-amorphization implantation (Ge-PAI), low-energy B implantation and non-melt laser annealing is a promising method to form highly-activated, abrupt and ultra-shallow junctions (USJ). In this work, shallow p+/n junction was formed by annealing the implanted sample with two different laser sources, i.e. by using excimer laser, KrF (λ= 248nm, pulse duration : 37ns) and green laser (λ= 527nm, pulse duration : 110ns) in order to compare the diffusion of boron during the formation of shallow p+/n junction. Experimental results show that remarkable boron diffusion occurred during annealing of the samples subjected to KrF laser annealing with a very short annealing time. Meanwhile, boron diffusion is controlled in the samples subjected to green laser annealing. We considered that the penetration depth and the pulse duration are the important factor that may caused the difference in boron diffusion during annealing process.