大尺寸直拉单晶硅的“增效降本”是当前光伏企业急需解决的问题。本文采用有限元体积法对φ300 mm直拉单晶硅生长过程分别进行稳态和非稳态全局模拟, 研究提高拉晶速率对直拉单晶硅生长过程中的固液界面、点缺陷分布以及生长能耗的影响。结果表明: 拉晶速率提高为1.6 mm/min时固液界面的偏移量为33 mm, 不会影响晶体的稳定生长; 拉晶速率对晶体中点缺陷的分布起决定性作用, 提高拉晶速率不仅能降低自间隙点缺陷的浓度, 而且使晶棒内V/G始终高于临界值; 且拉晶速率对功率消耗影响较大, 提高拉晶速率后晶体生长时间减少了46.4%, 单根晶体生长消耗功率降低了约4.97%。优化和控制适宜的拉晶速率有利于低成本地生长特定点缺陷分布甚至无点缺陷单晶硅, 为提高大尺寸直拉单晶硅质量、降低生产能耗提供一定的理论支持。

The “efficiency and cost reduction” of large size Czochralski monocrystalline silicon is an urgent problem for photovoltaic enterprises. In this paper, the finite element volume method was used to simulate the growth process of φ300 mm Czochralski monocrystalline silicon in both steady and unsteady state, respectively, to study the change rule of crystal-melt interface, point defect distribution and growth energy consumption during the growth process of Czochralski monocrystalline silicon by increasing the pulling rate. The results show that the shift of crystal-melt interface is 33 mm when the pulling rate increases to 1.6 mm/min, which would not affect the stable growth of crystals. The pulling rate plays a decisive role in the distribution of point defects in the crystal. Increaseing the pulling rate could not only reduce the concentration of self-interstital defects, but also make the V/G in the crystal bar always higher than the critical value. And the pulling rate has a great influence on the power consumption. After increasing the pulling rate, the crystal growth time is reduced by 46.4%, and the power consumption for monocrystalline silicon growth is reduced by 4.97%. Optimization and control of appropriate pulling rate is conducive to low cost growth of specific point defect distribution or even point defect free monocrystalline silicon, which provides some theoretical support for improving the quality of large size Czochralski monocrystalline silicon and reducing production energy consumption.