Thermal Field Optimization Through Numerical Simulation for the Growth of High Quality GaSb Single Crystal

As an important III-V semiconductor material for infrared applications, gallium antimonide (GaSb) single crystals require high quality with excellent lattice perfection, making it necessary to establish an ideal thermal field during the liquid encapsulated Czochralski (LEC) growth process. In this study, global transient numerical simulations are carried out to analyze the effects of growth parameters on the temperature distribution, melt convection structure, and solid-liquid interface deflection during the LEC growth of 3-inch-diameter GaSb crystals. Additionally, an innovative bottom heater is introduced to optimize the thermal distribution. The simulation results demonstrate that the number of melt vortices decreases from three to two when the crucible rotation rate is 2 rpm, significantly reducing the solid-liquid interface deflection. A pulling rate of 8 mm/h reduces local overheating at the interface, thereby minimizing deflection and promoting stable growth. The addition of a bottom heater improves the melt temperature distribution, reduces melt flow intensity, and enhances interface flatness. The average etch pit density (EPD) of the 3-inch (100) GaSb substrate is reduced from 2842 to 147 cm(-)2 after thermal field optimization, demonstrating a 94.8% reduction in dislocation density. This work establishes a scalable framework for the optimization of compound semiconductor crystal growth.