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溶液法是生长低缺陷高品质碳化硅(SiC)单晶的重要方法, 针对6英寸溶液法生长SiC单晶系统, 建立了感应加热和热质传递全局数值分析模型, 考虑了洛伦兹力、离心力、热浮力以及表面张力对溶液流动的耦合作用, 研究了晶体旋转对溶液中速度场、温度场、碳浓度场、晶体生长速率以及坩埚壁面碳溶解析出的影响规律. 结果表明, 溶液中洛伦兹力的存在使得低晶体转速下的流场十分复杂, 晶体转速需要控制在合适的范围内, 使得生长界面下方由输运决定的碳浓度分布与生长界面处由温度决定的碳浓度分布相协调, 才能获得均匀且高的SiC单晶生长速率. 晶体转速过小使得SiC单晶生长速率很低, 过大导致生长速率径向均匀性下降, 转速为25 r/min时SiC单晶的平均生长速率较高且沿径向分布均匀性较好. 进一步分析了溶液-坩埚交界面碳组分的溶解和析出, 定位了坩埚壁面溶解较快区域和SiC多晶颗粒生成区域, 并结合速度场预测了多晶颗粒的去向. 研究结果为溶液法生长6英寸SiC单晶提供了科学依据.The top-seeded solution growth (TSSG) method is a critical technique for growing low-defect and high-quality silicon carbide (SiC) single crystals. A comprehensive numerical analysis model including induction heating, heat and mass transfer is developed for growing 6-inch SiC single crystals. The coupling effects of Lorentz force, centrifugal force, thermal buoyancy force and surface tension on the solution flow are considered, and the effects of crystal rotation speed on the velocity field, temperature field, carbon concentration field, crystal growth rate and carbon dissolution and precipitation on the crucible wall are systematically investigated. The results indicate that the Lorentz force in the solution results in a more complex flow field at low crystal rotation speeds. The crystal rotation speed should be controlled within the appropriate range to ensure that the carbon concentration distribution beneath the growth interface determined by the transport mode is coordinated with that at the growth interface determined by the temperature, which is beneficial for the uniform and high growth rate of SiC single crystals. Low rotation speeds reduce the growth rate of SiC single crystals, while high rotation speeds lead radial uniformity of growth rate to decrease. At a rotation speed of 25 r/min, the average growth rate of SiC single crystals is higher and the radial distribution uniformity is better. Further analysis is conducted on the dissolution and precipitation of carbon at the solution-crucible interface, and the regions, where the crucible wall dissolves quickly and SiC polycrystalline particles are generated, are located. The transport directions of polycrystalline particles are predicted based on the velocity field. The research results provide a scientific basis for growing 6-inch SiC single crystals by TSSG method.
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Keywords:
- top-seeded solution growth /
- silicon carbide single crystal /
- crystal rotation /
- numerical simulation








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