Diffusion of co-implanted carbon and boron in silicon and its effect on excess self-interstitials

Diffusion of co-implanted carbon (C) and boron (B) in silicon (Si) and its effect on excess Si self-interstitials (I's) after annealing at 800 and 1000°C were investigated by means of secondary ion mass spectrometry. The experimental results showed that C diffusion was not significant at 800 and 1000°C but later became visible for longer annealing times at 1000°C. B diffusion was reduced by the presence of C when no significant C diffusion was observed, but it was enhanced when C diffusion was observed. These results indicate that all implanted C atoms form immobile CI clusters with excess I in the amount of implanted C and that these CI clusters are stable and trap I to reduce B diffusion. On the contrary, CI clusters are dissolved to emit I for longer annealing times at 1000°C and both B and C diffusion are enhanced. Diffusion simulation based on these models fits the experimental profiles of B and C.