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论文类型：期刊论文

发表时间：2016-03-01

发表刊物：VACUUM

收录刊物：EI、SCIE

卷号：125

页面范围：40-47

ISSN号：0042-207X

关键字：Silicon; Directional solidification; Process parameters; Crystal growth rate

摘要：A numerical model is proposed to investigate influences of process parameters, including crucible pulling down rates and heater temperature, on crystal growth rates for silicon purification by vacuum directional solidification. The crystal growth rates of a silicon ingot are analyzed based on the interface energy balance equation combining with the temperature field calculated by software of ProCAST, and the segregation behavior of impurities is investigated with the Scheil's equation. The results show that the crystal growth rates decrease linearly with the increase of heater temperature at a fixed value of the crucible pulling down rate, and increase exponentially with the increase of the crucible pulling down rates at a fixed value of the heater temperature. The numerical model is verified by removal of iron impurity from 300 ppmw to 1 ppmw and by the temperature of melt silicon which is recorded by a thermocouple. The results show that numerical results agree well with experimental results. This research is used for adjusting process parameters to control crystal growth during silicon purification by directional solidification. (C) 2015 Elsevier Ltd. All rights reserved.