Ultra-shallow junction formation by Point Defect Engineering

Abstract

Point Defect Engineering (PDE) using high-energy ion bombardment can be used as a method to inject vacancies near the surface region with excessive interstitials created near the end of the projected range deep inside the substrate. We demonstrate that PDE not only suppresses transient enhanced diffusion of B in Si caused by implantation-induced defects, but also suppresses boride-enhanced diffusion normally associated with a high B concentration layer. With PDE, we can retard B diffusion, sharpen boron profile and increase B activation. An enhancement of substitutional ratio of B was observed by aligned nuclear reaction analysis. By drive-in diffusion of B from a surface deposited layer, the concept of boron diffusion control was used as an approach to form sub-10 nm ultrashallow junctions in Si.