Suppression of Inclusions in Solution Growth SiC Crystals from Cr–Si–Ce–Al Solvent

This study systematically investigates the suppression of inclusions in solution growth SiC crystals by employing the Cr–Si–Ce–Al solvent system, where 10% of Si is strategically substituted with Ce to reduce melt viscosity, while Cr content is varied. Nondestructive computed tomography (CT) imaging revealed that increasing Cr content, while maintaining a relatively fixed Ce addition, progressively reduced solvent inclusions. Notably, the Cr-40 (Si0.9Ce0.1)-4 Al composition successfully eliminated inclusions while maintaining stable 4H–SiC growth, though at a reduced growth rate of 70 μm/h compared to 90 μm/h for Cr-45 (Si0.9Ce0.1)-4 Al. A critical phase stability boundary was identified at Cr-35 (Si0.9Ce0.1)-4 Al, where the quaternary compound CeCr2Si2C coprecipitates with SiC, establishing an upper limit for Cr content in the solvent system. Preliminary experiments across various solvent compositions revealed that SiC remains the only stable solid phase at lower Cr content (50%–55%), whereas at 60% Cr, increased carbon solubility promotes the formation of chromium carbide during cooling. The optimized solvent composition achieves a balance between enhanced carbon dissolution capacity from increased Cr content and reduced viscosity effects due to Ce addition, providing a pathway for producing inclusion-free SiC crystals suitable for high-performance electronic applications.