Thermal Field Simulation and Optimization for 8 in. SiC Crystal Growth via Novel Resistance Furnace Design.

Silicon carbide (SiC), a wide-band gap semiconductor, is essential for applications in electric vehicles, 5G communications, and aerospace due to its outstanding physical properties. However, their high production costs limit their widespread industrial applications. The growth of larger diameter and thicker crystals, particularly 8 in. crystals, offers the potential to reduce these costs. Therefore, large-diameter PVT crystal growth equipment with resistance heating has become a focal point of research in this field. In this paper, a novel double-flap resistance furnace design is proposed for the first time, and the thermal field is systematically studied by three-dimensional COMSOL Multiphysics modeling to optimize the growth of 8 in. 4H-SiC single crystals. It is found that the resistance heating system significantly outperforms the induction heating system by providing a lower radial temperature gradient necessary for large-diameter SiC crystals. Additionally, the influence of key parameters such as the crucible, the distance between the heater and the crucible, and the growth power on the thermal field distribution in the crucible was also systematically studied. The influence of the distance from the surface of the source material to the crystal surface and the distance from the center of the crystal to the edge on both the axial and radial temperature differences is also analyzed. Based on the simulation results, the crystal growth scheme was further optimized and an 8 in. SiC crystal with a thickness above 20 mm and resistivity uniformity was successfully obtained using the novel resistance furnace. This is of great significance for the growth of large-diameter SiC crystals.