Improving the Purity of Multicrystalline Silicon by Using Directional Solidification Method
Large temperature gradient was introduced to improve the removal rate of metal impurity in silicon ingot during direction solidification. The concentration of metal impurities in the silicon ingot with a large temperature gradient is 0.96 ppmw. The solidification time is reduced by 20% due to the fast speed of crystal growth improved; meanwhile the purity is increased by 64%.
P. T. Li et al., "Improving the Purity of Multicrystalline Silicon by Using Directional Solidification Method", Materials Science Forum, Vol. 911, pp. 51-55, 2018