Dynamic deformation modeling for the interfaces of growth, etching, and deposition under switching flow in TSSG-SiC growth

Abstract

The top-seeded solution growth (TSSG) method is promising for growing high-quality, large-size bulk silicon carbide (SiC) crystals and is being applied in mass production. Quasi-steady global modeling is almost the standard method for optimizing hot-zone and process parameters. For the first time, a transient global model was developed to simulate solution flow, mass transport, and dynamic geometry changes during the TSSG-SiC process. The switching flow condition, achieved through dynamic control of crucible and crystal rotations, was incorporated into the growth simulation. Carbon dissolution, transport, and incorporation were coupled within this transient global modeling. Generalized boundary conditions for growth, etching, and deposition interfaces were implemented to model dynamic interface deformation. Fast crucible rotation induced an inward flow, leading to a large carbon concentration gradient and rapid but non-uniform SiC crystal growth. Conversely, strong crystal rotation generated an outward flow, resulting in homogeneous carbon distribution and slow but uniform SiC crystal growth. Consequently, the carbon transport under switching flow caused periodic fluctuations in growth, etching, and deposition rates. Furthermore, we utilized our transient model to optimize the final crystal shape by adjusting the duration ratio between inward and outward flow periods. This dynamic process modeling enables the optimization and adaptive control of growth conditions for cost-effective TSSG-SiC crystal growth.