Impact of carbon on diffusion and activation of arsenic in silicon

We successfully characterized an influence of carbon (C) on diffusion and activation of arsenic (As) atoms in silicon (Si) with different C contents less than ~1 at.% and As concentrations higher than ~7 × 10¹⁹ cm^-3 after high-temperature annealing. It is experimentally found that As atoms segregate into interstitial site by C incorporation with an As concentration over ~1.4 × 10²⁰ cm^-3 after 1050 °C spike annealing, resulting in a decrease in the As activation ratio. This can be attributable that incorporated C atoms enhance a formation of inactive As vacancy cluster. In addition, Hall mobility is decreased with increasing C content, which may be interpreted in terms of the lattice strain and the point defects generated by the C incorporation. Furthermore, no significant impact of C on the As-diffusion is observable in the As-implanted layer with a fluence higher than 5 × 10¹⁴ cm^-2 after 1050 °C spike annealing. As a result, the C incorporation marked increase the sheet resistance (ρ_s) of the As activation layer in Si.