Interstitial carbon-substitutional tin center in silicon(?)

Electron-irradiated n-type silicon doped with carbon and tin has been studi ed by infrared absorption spectroscopy. In addition to the well known signa ls of interstitial carbon, C-i, and the dicarbon center, C-s-C-i, three new lints at 873.5, 1025, and 6875 cm(-1) are observed in the spectra. The 873 .5 and 1025 cm(-1) lines are located in a region characteristic of the loca l vibrational modes of interstitial carbon in silicon. Similarly, the frequ ency of the 6875 cm(-1) line is very close to the electronic transition of C-i at 6903 cm(-1). Based on the annealing kinetics of these lines as well as those belonging to C-i and C-s-C-i, we tentatively identify the center r esponsible for the 873.5, 1025, and 6875 cm(-1) lines as interstitial carbo n perturbed by tin, which is located at one of the neighboring substitution al lattice sites. (C) 2001 Elsevier Science B.V. All rights reserved.