Carbon-tin defects in silicon - art. no. 125212

Infrared absorption experiments and ab initio computer simulations are used to study tin-carbon centers in silicon. Electron irradiation of C and Sn d oped Si leads to prominent absorption lines at 873.5 and 1025 cm(-1). These are assigned to a carbon interstitial trapped by a substitutional Sn atom. The calculated modes are in good agreement with those observed. The calcul ations also suggest that a close-by pair of substitutional C and Sn will be a stable but electrically inert defect. This defect may account for the ex perimentally observed drop in the concentration of the C-s-C-i defect after a room temperature annealing. Finally, we suggest Sn-C codoping of Si for manufacturing of radiation hard silicon.