Thermodynamics of solid silicon equilibrated with Si–Al–Cu liquid alloys

Abstract

For discussing the addition of copper to the Si–Al solvents in the LPE growth of silicon and that in the solidification refining of silicon, the solubilities of aluminum at 1173, 1273, and 1373 K and copper at 1273 and 1373 K in solid silicon in equilibrium with liquid Si–Al–Cu alloys were investigated. Solubilities of aluminum and copper were determined by employing the temperature gradient zone melting method and diffusion experiment, respectively. The activity coefficient of copper in solid silicon at infinite dilution relative to the pure solid state was determined as follows R T ln γ Cu ( s ) in solid Si 0 = 166 , 000 ( ± 3500 ) − 47.6 ( ± 2.8 ) T ( J / mol ) ( 975 – 1602 K ) Copper additions to the Si–Al solvents decreased aluminum solubilities in solid silicon effectively and the contents of copper introduced into solid silicon were found to be fairly small.