Abstract
Stable isotopes in the silicon crystals synthesized by floating zone (FZ) method have been found to be heterogeneously distributed by means of SIMS analysis (Morishita and Satoh, 2003). It is necessary to know the exact temperature condition during FZ growth because isotope can be partitioned into solid as a function of the growth temperature. We applied in-situ measurement of melt temperature for a floating zone (FZ) system. This measurement enables evaluation of thermal condition during FZ crystal growth under various growth rates (0-46 mm/hr). Fast FZ growth of silicon at 46 mm/hr accompanies with 〜0.8 mm shift-down in the level of the crystal/melt interface. In this FZ Si-growth condition, the melt supercooling was estimated to be up to 130K. Growth rate R was simply formulated as R=0.299 × ΔT for this experimental condition. For a given growth rate, supercooling cannot be ignored and needs to be taken into account for the evaluation of stable isotope fractionation between solid and melt.
