关键词: 直拉单晶硅, 有限元体积法, 拉晶速率, 固液界面, 点缺陷, 生产能耗

Abstract: 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 ø300 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.

Key words: Czochralski monocrystalline silicon, finite element volume method, pulling rate, crystal-melt interface, point defect, energy consumption