Rapid Thermal Annealing of Pre-Amorphized B and BF2-Implanted Silicon

Abstract

ABSTRACTShallow p+n junctions have been formed through a combination of pre-amorphization of the silicon surface by implantation of 28Si, 33Ar, or 73Ge, low energy implantation of boron or BF2+, and rapid thermal annealing (RTA) in a tunqsten halogen lamp system. Both pre-amorphization and RTA are required to form a shallow (<0.25 μm) junction, for either boron or BF2+. Arqon pre-amorphization results in poor electrical activation of the boron, while germanium gives the lowest sheet resistivity, but is responsible for a deep boron tail during implantation. The residual damage is characterized by a plane of dislocation loops centred either close to the boron concentration peak, for B+ implantation into a crystalline substrate, or at the original amorphous-crystalline interface, for pre-amorphized specimens.