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

Abstract

This article reports some new experimental evidence for the effect of carbon on oxygen precipitation in a high carbon content Czochralski silicon (H[C] Cz-Si) crystal. The oxygen precipitation occurring at an intermediate temperature of 950 °C has been especially investigated. In such case, the carbon atoms slightly participate in oxygen precipitation with 1200 °C preannealing, while the carbon atoms actively participate in oxygen precipitation with low temperature preannealing. The experiments show that the 1230 cm−1 absorption band in the Fourier transmission infrared spectrum definitely originates from the oxygen precipitates involving insignificant carbon reduction; on the other hand, the oxygen precipitates involving significant carbon reduction are surely irrelevant to the 1230 cm−1 absorption band. According to the correlation of the change in oxygen and carbon concentrations 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 precipitation when the precipitates are smaller than the critical size; whereas, the carbon atoms are only slightly involved in oxygen precipitation when the precipitates are larger than the critical size.