Evidence for the effect of carbon on oxygen precipitation in Czochralski silicon crystal

This article reports some new experimental evidence for the effect of carbo n on oxygen precipitation in a high carbon content Czochralski silicon (H[C ] Cz-Si) crystal. The oxygen precipitation occurring at an intermediate tem perature of 950 degrees C has been especially investigated. In such case, t he carbon atoms slightly participate in oxygen precipitation with 1200 degr ees C preannealing, while the carbon atoms actively participate in oxygen p recipitation with low temperature preannealing. The experiments show that t he 1230 cm(-1) absorption band in the Fourier transmission infrared spectru m definitely originates from the oxygen precipitates involving insignifican t carbon reduction; on the other hand, the oxygen precipitates involving si gnificant carbon reduction are surely irrelevant to the 1230 cm(-1) absorpt ion band. According to the correlation of the change in oxygen and carbon c oncentrations during oxygen precipitation, it is plausible that there is a critical precipitate size which distinguishes the carbon behavior in oxygen precipitation, that is, the carbon atoms actively participate in oxygen pr ecipitation when the precipitates are smaller than the critical size; where as, the carbon atoms are only slightly involved in oxygen precipitation whe n the precipitates are larger than the critical size. (C) 2000 American Ins titute of Physics. [S0021-8979(00)04606-5].