3D numerical modeling and simulation of β-Ga₂O₃ crystal growth by edge-defined film-fed growth method

Numerical simulation is an effective approach for improving the edge-defined film-fed growth (EFG) of β-Ga₂O₃ crystals by studying the heat transfer, melt flow, and crystallization interface shape. However, the nonaxisymmetric structure of the EFG furnace, the anisotropy of the β-Ga₂O₃ crystal, the infrared radiation absorption by free carriers, and the tracking of three-dimensional (3D) crystallization interface shape bring challenges in modeling and simulation. In this study, a global 3D nonaxisymmetric numerical model was established for the growth of ribbon β-Ga₂O₃ crystals. The anisotropic thermal conduction coupled with the thermal radiation inside the crystal was considered, and the dynamic mesh technique was developed to track the severely deformed crystallization interface. Subsequently, the numerical model was used to study the influences of thermal radiation absorption by free carriers on temperature distribution and crystallization interface shape. The results indicate that the thermal radiation absorption inside the crystal directly affects the shape of the crystallization interface and the stability of crystal growth. Strong radiation absorption leads to a concave crystallization interface, whereas the concavity of the interface shape exhibits a decreasing trend with the increase of crystal height, which is beyond expectation. All these phenomena are related to the heat transfer and temperature distribution in the EFG furnace, and the 3D numerical modeling and simulation are helpful in deeply understanding the reasons behind the phenomena and improving the β-Ga₂O₃ crystal growth.