Effects of implant temperature on process characteristics of low energy boron implanted silicon

The effects of self-amorphization thickness on boron (B) dopant depth profile in silicon (Si) were investigated by cold temperature implant, down to −100°C. Significant B junction depth (Xj) reduction can be achieved for as-implant and post anneal, when the self-amorphization thickness is comparable or deeper than the B implant projected range (implant peak position) and the implant is completed at sufficiently low temperature. There is a transition temperature regime before the appropriate temperature is reached. The Xj reduction is stagnated due to the thickness limitation and the degree of self-amorphization. Temperature dependent surface damage, self-amorphization thickness, diffusion, and activation were also studied. Improvement in carrier mobility is more significant in certain dose regimes at low temperatures. The findings of this study provide important insight in to the control of the junction profile for smaller atomic mass unit (AMU) species, like B, by using the self-amorphization effect at cold temperatures.