Oxygen precipitation and thermal donor formation in Czochralski-grown silicon doped with carbon and tin

The effect of carbon and tin on the oxygen precipitation and the thermal donor formation in Czochralski-grown silicon after an extended isochronal anneal in the temperature range between 400 and 900 °C has been studied. The experimental results indicate that the oxygen precipitation in both carbon- and tin-doped silicon is enhanced. In carbon-doped silicon, the formation of the thermal donors is suppressed. No effect of tin on the thermal donor formation is observed. Based upon the hard-sphere model, it is hypothesized that the lattice strain arising from the size misfit between the doping impurities and silicon atoms can play an important role in the oxygen precipitation in a heavily doped silicon.