Time and Temperature Dependence of the Solubility of Carbon in Liquid Silicon Equilibrated with Silicon Carbide and Its Dependence on Boron Levels

Abstract

The solubility of carbon in liquid silicon equilibrated with silicon carbide has been studied in the temperature region 1414–1559°C. High purity silicon was melted in graphite crucibles under Ar atmosphere with various boron additions. The equilibrium was observed to be established within minutes, after which no evolution with time could be observed. The addition of boron to the system was found to increase the carbon solubility, and an equation was derived describing the solubility as a function of both temperature and boron content. The solubility of carbon in pure liquid silicon was determined to be 65 ppm mass at the melting point of silicon. Expressions for the dissolution energy of carbon and the B-C interaction coefficient were also derived.