Global Investigation on Thermodynamic Properties of the Si–Cr Solvent for SiC Growth

Thermodynamic properties of solvents in high-temperature solution growth of SiC crystals are essential for understanding the growth mechanism and designing new solvent systems. In this study, we performed a “global” investigation of the thermodynamic properties of Si–Cr solvents through a thermodynamic calculation based on reliable carbon solubility data. Solvent samples were prepared using two different crucibles, and the effect of different carbon sources on the solvent composition was analyzed. The reliable carbon solubility of Si–Cr solvents with different compositions was obtained through chemical composition analysis. Based on the experimental data, ternary liquid-phase interaction parameters were optimized and were applied to calculate the thermodynamic properties of the Si–Cr solvent system. A global investigation of Si1–xCrx solvents (x ranging from 0 to 1 and temperature from 1700 to 1850 °C) indicates that the Si–Cr system exhibits a uniquely broad high-supersaturation region. This region distinguishes the Si–Cr solvents from other Si–M systems (M = Mn, Fe, Co) and provides significant advantages for rapid crystal growth. Based on the evaluation of previously reported Si–Cr solvents, supersaturation and viscosity are identified as crucial factors in controlling the growth rate of SiC crystals. Overall, this work not only elucidates why Si–Cr serves as the mainstream solvent system for SiC growth but also offers a paradigm for the analysis of thermodynamic properties of the solvent systems.