Silicon isotope fractionation during FZ growth of silicon crystals

摘要

We have carried out evaporation and crystal growth experiments, and precisely determined silicon isotopic ratios for the run products of the experiments using the ims-1270 SIMS with multicollectors at the Geological Survey of Japan. The silicon isotope fractionation factor between vapor and melt under vacuum was determined to be 0.9821 at a temperature of 1680 ℃, while that under 10~5 Pa of Ar was 0.9947. The SIMS microanalysis revealed isotopic zoning in a single silicon crystal which was produced during its growth. It is inferred that the silicon isotopic ratios in a silicon crystal during the floating zone growth were controlled by the growth conditions such as the growth and rotation rates as well as the fractionation factor between the crystal and its melt.