Large scale purification of metallurgical silicon for solar cell by using electron beam melting

Abstract

The large size electron beam furnace has been used to remove phosphorus from metallurgical grade silicon pretreated with effective removal of boron and metals. The content of phosphorus decreases from 15ppmw to about 0.1ppmw after the electron beam treatment in a short time. More than 500kg silicon is melted and purified in the furnace in a run, indicating its feasibility for large scale industry application. The purified UMG silicon was casted into multicrystalline silicon ingot by a standard technology and multicrystalline silicon wafers were obtained for solar cell fabrication. By using a commercial production line, solar cells made from the multicrystalline silicon wafers exhibit good performance with an average conversion efficiency of 16.1%.