Numerical simulation of thick SiC crystal based on ring-shaped powder structure

Silicon carbide (SiC) has important application prospects in power and radio frequency (RF) devices. However, the expensive SiC substrate is a key factor restricting the cost of the devices. Developing large-diameter and thick SiC crystal growth technology is expected to reduce the cost of SiC substrate. Currently, challenges such as limited thickness, elevated thermal stress, and high defect density remain in SiC crystal growth. Based on simulation tools, the effect of the powder size and the distance between the seed and powders surface on thermal field, crystal thickness and dislocation density are analysed. Then, a ring-shaped powder structure is proposed to enhance both the growth rate and the quality of the crystal. Simulations with different powder sizes in the inner circle and outer ring reveal that when the powder sizes are 500 μm in the inner circle and 10,000 μm in the outer ring, a uniform temperature field, a rapid crystal growth rate, and a low dislocation density can be achieved. Additionally, by optimizing the insulation structure, the crystal achieves a slightly convex surface and a lower dislocation density. The results indicate that the ring-shaped powder structure can enhance powder utilization, enable the growth of thick crystals, and reduce dislocation density.