Measurement of nonthermal illumination-enhanced diffusion in silicon

Continued scaling of ultrashallow junctions in transistor devices raises the possibility that new physical effects connected with intense lamp illumination during rapid thermal annealing (RTA) need to be incorporated into models for transient enhanced diffusion (TED). Identification of such effects is difficult in conventional RTA geometries because lamps provide both heating and photostimulation, and because the interpretation of conventional dopant diffusion experiments is impeded by complex dopant-defect interactions and the presence of built-in electric fields in typical test structures. In this paper we present strong experimental evidence of nonthermal illumination-enhanced diffusion in unimplanted silicon.