Thermal Field Optimizationand Structural Defect Suppressionin VGF-InP Single Crystals: A Study Based on Orthogonal Design andCGSim Simulation

Abstract The thermal field distribution during the vertical gradient freeze (VGF) growth of indium phosphide (InP) single crystals significantly influences the formation of structural defects such as dislocations, residual stress, and twins. This study combines CGSim numerical simulations with experimental validation to systematically elucidate the relationships between the growth parameters, solid–liquid interface morphology, and defect formation. Based on a 4-in. VGF-InP crystal growth furnace, a CGSim model was established to simulate the effects of the axial temperature gradient, growth rate, and crucible angle on the thermal/flow fields, dislocation/stress distribution, and interface evolution. Key growth parameters were optimized through orthogonal experimental design. InP single crystals were then grown experimentally, and their quality was evaluated using dislocation density, photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), and Raman spectroscopy. The results indicate that the crucible angle and growth rate primarily govern the flow field symmetry, velocity uniformity, and thermal stress accumulation, thereby regulating dislocation multiplication and interface stability. This “simulation-optimization-validation” paradigm, along with the determined parameter hierarchy (crucible angle > growth rate > axial temperature gradient), provides a practical optimization pathway and mechanistic insights for fabricating low-dislocation, low-stress InP single crystals via the VGF method.