Effect of Calcium on Thermodynamic Properties of Boron in Molten Silicon

摘要

Removal of boron is one of the major problems on the purification of silicon for solar cells. In order to clarify the possibility of its removal by acid leaching with calcium addition, the effect of calcium on thermodynamic properties of boron in molten silicon was studied. The interaction parameter between boron and calcium in molten silicon was determined as the negative value ε_B~(Ca) = -3.08 +-0.84 at 1723K and the practical leaching treatment was found to promote the removal ratio of boron up to 40% when 6.2% of calcium was contained in molten silicon.