Ultrafast interstitial injection during transient enhanced diffusion of boron in silicon

Abstract

The injection of interstitials during annealing of nonamorphizing Si implants has been monitored by means of sharp boron-doped marker layers grown by reduced pressure chemical vapor deposition. The boron diffusivity enhancement measured during the initial annealing stages (t<15 s) at 700 °C is at least an order of magnitude larger than the enhancement during subsequent annealing. The high supersaturation of interstitials during the early stages of the anneal induces immobilization of boron down to concentrations of ≊1×1017 cm−3, consistent with interstitial-driven boron clustering. The ultrafast diffusion sets lower limits for the silicon and boron interstitial diffusivities at 700 °C of 2×10−10 cm2 s−1 and 2×10−13 cm2 s−1, respectively.