Numerical Simulation Of Oxygen Distribution At The Solid-liquid Interface For CZ Crystal Growth In Horizontal Superconducting Magnetic Field

Silicon single crystal as the basic material in the field of integrated circuit and solar photovoltaic power generation, its quality has a direct impact on the performance of electronic devices. The CZ method is the main method of growing silicon single crystal at present. The flow, heat transfer and mass transfer of the melt in the crucible during the crystal growth process, especially the oxygen impurity content of the solid-liquid interface and the uniformity of the oxygen impurity distribution directly affect the silicon single crystal quality. In order to improve the quality of the large-scale silicon crystal, it is necessary to analyze the distribution characteristics of oxygen impurity at the solid-liquid interface to better guide the actual production of silicon single crystal.Facing the crystal growth process, there are many problems such as thermal field coupling,heat and mass transfer coexist, boundary conditions blurry, chemical changes are intertwined and interact with each other and mechanism modeling difficult. Numerical simulation based on finite volume method is an effective way to solve this problem. At present, the study of oxygen transfer in the melt has been quite mature in the 2D or 3D environment, however, the oxygen distribution at the solid-liquid interface in the 3D environment is rarely studied. In this paper,the three-dimensional numerical simulation of the finite volume method is used, based on the 2D/3D hybrid model, the oxygen concentration distribution at the solid-liquid interface during the crystal growth process in the conventional magnetic field (800-1000 Gauss) is studied and analyzed. The effect of the process parameters for the oxygen concentration and the uniformity of radial oxygen concentration distribution at the solid-liquid interface are analyzed in the horizontal superconducting magnetic field structure with low power consumption and high field strength, meanwhile, the influence of the quadrupole magnetic field structure on the oxygen concentration distribution at the solid-liquid interface is investigated in the superconducting magnetic field space.The results show that increasing the diameter of crystal, so that the flow in the melt is enhanced, the oxygen concentration increases at the solid-liquid interface, and the radial oxygen concentration distribution at the solid-liquid interface is more uniform. The superconducting magnetic field effectively solves the problem that the oxygen concentration is too high during the large-scale crystal growth process in the conventional magnetic field. Increasing the intensity of the superconducting magnetic field, so that the oxygen concentration decreases at the solid-liquid interface, and the radial oxygen concentration distribution at the solid-liquid interface is more uniform; Crucible rotation speed is suitable for adjusting the oxygen concentration and the uniformity of oxygen concentration distribution in the low rate and small range; Crystal rotation speed can adjust the consistency of the solid-liquid interface shape and the oxygen concentration and the uniformity of oxygen concentration distribution at the solid-liquid interface in a large range; The method of technological adjustment in the early and middle stage of crystal growth should be low crucible rotation speed and low crystal rotation speed, for the later stage of crystal growth, the higher crucible rotation speed and lower crystal rotation speed are suitable.