Modeling of convective transport in crystallization of gallium nitride by basic ammonothermal method

The most important parameter affecting the surface morphology of the growing crystal and its structural quality is supersaturation at the crystallization front. In the case of ammonothermal growth of gallium nitride, supersaturation is fully related to convective mass transport. Due to technological limitations and extreme crystallization conditions it is problematic to obtain detailed information about the internal processes in the growth experiments, especially the convective flow. The solution to this problem is to use the Computational Fluid Dynamics method to model the processes occurring inside autoclaves. This paper presents a quantitative analysis of convective transport in a three-dimensional approximation during the ammonothermal crystallization of gallium nitride. ANSYS Academic Computational Fluid Dynamics simulation software was used. The simulation results obtained were referenced and compared with the experimental results: thickness and structural quality of the gallium nitride crystals.