Effect of near-surface band bending on dopant profiles in ion-implanted silicon

Abstract

Recent experimental work has demonstrated the existence of band bending at the Si–SiO2 interface after ion implantation. The present work employs FLOOPS-based numerical simulations to investigate the effects this bending can have upon dopant profiles that evolve during transient enhanced diffusion in post-implant annealing. In the case of boron, band bending induces significant junction deepening because the near-interface electric field repels charged interstitials from the interface. Band bending also provides a mechanism to explain the pile-up of electrically active boron within ∼1 nm of the interface. The results suggest that conflicting literature regarding the capacity of the interface to absorb interstitials can be rationalized by a modest inherent absorbing capability coupled with band bending.