Numerical modeling of the thermal field and chemistry assessment of SiC crystal growth in PVT furnaces

Silicon carbide (SiC) is a key material for high-power, high-temperature, and high-frequency applications. The physical vapor transport (PVT) method remains the leading approach for growing high-quality SiC crystals. Numerical modeling is essential for understanding and optimizing SiC bulk crystal growth. This study highlights the importance of high-fidelity radiation modeling in optimizing the PVT process for SiC crystal growth. Using COMSOL Multiphysics simulations, different radiation models, such as hemicube and ray shooting, are tested and compared. To describe the growth process, a physical growth model and considerations for chemical reactions, vapor species transport, and the kinetics of decomposition and deposition are utilized. The Hertz-Knudsen relation is coupled to the activities of silicon and carbon to predict both the growth rate and the evolving crystal shape. The coupled model quantifies how axial and radial thermal gradients along the seed and source influence species fluxes, local growth rates, and crystal shape across three different operating scenarios. The results show that an optimized thermal field, together with controlled species fluxes, is critical for improving crystal quality by increasing the growth rate at the center and lowering it at the rim.