Purification of solar grade silicon using electromagnetic field

Abstract

Non-metallic particles and the metallic impurity elements in the solar cell silicon have a strong detrimental effect on the conversion efficiency of the solar cell. Removing these impurities is one of the important tasks for silicon refining. The current paper proposed a new approach to purify silicon - electromagnetic (EM) separation. Since the non-metallic particles and the metallic impurity elements are non- or less-conductive while the molten silicon is well conductive, under EM field, the Lorenz force will push the particles to the boundary layer, thus separate these inclusions. In the current study, a high frequency EM field was imposed on the silicon melt in laboratory scale experiments with a frequency of 60 kHz and 15.0 A current, the non-conductive SiC particles were successfully pushed to the boundary layer close to the crucible wall.