Rapid Thermal Processing and The Quest for Ultra Shallow Boron Junctions

Abstract

AbstractRapid Thermal Processing (RTP) can minimize processing time and therefore minimize dopant motion during annealing of ion implanted junctions. In spite of the advantage of short time annealing using RTP, the formation of shallow B junctions is thwarted by channeling, transient enhanced diffusion and concentration enhanced diffusion effects all of which lead to deeper B profiles. Channeling and transient enhanced diffusion can be avoided by preamorphizing the silicon before the B implant. However, defects at the original amorphous/crystal boundary persist after annealing. Very low energy B implantation can lead to very shallow dopant profiles and in spite of channeling effects, offers an attractive potential shallow junction technology. In all of the shallow junction formation techniques RTP is required to achieve both high activation of the implanted species and minimal diffusion of the implanted dopant.