Solvent refining of Si for solar cells using a Si-Sn solvent

摘要

Metallurgical routes for solar grade silicon (SOG-Si) offer benefits in productivity and process cost. Recently a novel refining technique, namely, solidification refining of Si using Si-Al solvent at low temperature, where the most of impurities can be removed by using the enhanced segregation, was proposed by our group. However, the growth rate of bulk Si was inadequate. We have then investigated the solvent refining of Si with a Si-Sn solvent [1] by focusing on the moderate liquidus slope in the phase diagram. In order to determine the effectiveness of solvent refining of Si with a Si-Sn solvent, a lab-scale continuous process of slag refining for B elimination followed by the solidification refining for removal of metallic impurities was conducted in the present work.