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JOURNAL OF SYNTHETIC CRYSTALS ›› 2023, Vol. 52 ›› Issue (9): 1641-1650.

• Research Articles • Previous Articles     Next Articles

Influence Mechanism of Crucible Rotation Rates on the Flow Field and Oxygen Concentration of the Semiconductor-Grade Czochralski Monocrystalline Silicon Melt under Transverse Magnetic Field

WANG Liguang1, RUI Yang1, SHENG Wang2, MA Yinshuang1, MA Cheng1, CHEN Weinan2, ZOU Qipeng2, DU Pengxuan4, HUANG Liuqing2,3, LUO Xuetao2,3   

  1. 1. Ningxia Research Center of Semiconductor-grade Silicon Wafer Materials Engineering Technology, Ferrotec (Ningxia) Semiconductor Co., Ltd., Yinchuan 750021, China;
    2. Xiamen Key Laboratory of Electronic Ceramic Materials and Devices, College of Materials, Xiamen University, Xiamen 361005, China;
    3. Shenzhen Research Institute of Xiamen University, Shenzhen 518063, China;
    4. Ningxia Polytechnic, Yinchuan 750021, China
  • Received:2023-02-13 Online:2023-09-15 Published:2023-09-19

Abstract: In this study, the influence mechanism of crucible rotation rates on the flow field and oxygen concentration of 200 mm semiconductor-grade Czochralski monocrystalline silicon under transverse magnetic field was investigated using ANSYS finite element software. The results show that flow field and oxygen concentration distribution of the silicon melt exhibit three-dimensional asymmetry under transverse magnetic field. The convective forms of the melt mainly include Taylor-Proundman vertices, buoyance-thermocapillary vortices, and secondary vortices. The former two contributed to the volatilization of oxygen, while the latter one had a suppressing effect. When the crucible rotation rate is low (0.5~1.0 r/min), the weaker convective strength of the melt results in low thermal conductivity efficiency between the crucible wall and the solid-liquid interface, and oxygen mainly migrates to the solid-liquid interface through a diffusion mechanism, resulting in high oxygen concentration in silicon melt. When the crucible rotation rate is high (2~2.5 r/min), oxygen migrates to the solid-liquid interface through strong convective forms. As the crucible rotation rate increases, the strength of the secondary vortices and buoyancy-thermocapillary vortices increases, and the region affected by the latter moved away from the free surface, resulting in a trend of first decreasing and then increasing oxygen concentration in the silicon melt. Both the numerical simulation results and experimental results indicate that a crucible rotation rate of 1.5 r/min is optimal for obtaining monocrystalline silicon with lower average oxygen concentration. The results of comparative analysis between experiments and numerical simulations can provide a reference basis for optimizing the parameters of the crystal growth process under transverse magnetic field.

Key words: ANSYS finite element software, 200 mm semiconductor-grade monocrystalline silicon, Czochralski method, crucible rotation rate, flow field, oxygen concentration

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