| Recently, the development of PV industry depends on the decreasing productive costs and the increasing photoelectric efficiency. Enhancing the productivity of crystal silicon plays an important role in reducing the costs. The typical technique is enlarging the charge mount of material. But it intensifies the natural convection of the melt, which increases the oxygen concentration and the carbon concentration. Thus the photoelectric transformation efficiency is suppressed. Furthermore, the application of magnetic field could help reduce the concentration effectively. But it is against the cost demand. Anyway, the ideal resolution is advancing the pull speed by improving the distribution of hot zone and increasing the release rate of crystallization heat.The conventional argon guide system is modified inΦ200 mm CZSi growth. Meanwhile, numerical simulation is conducted by the finite element method. The experimental results indicate that the hot zone is optimized by the new composite guide system. The vertical temperature gradient increases both in the melt and in the crystal after improvement. Pull speed is averagely advanced to 0.9 mm/min and the stability of the process is improved.The traditional thermal field in a TDR-80 CZSi furnace is improved. Mathematical modelings under different conditions are built. Meanwhile, numerical simulation is conducted by the finite element method. Effects of the extend ratio of double-heater, crucible size and melt height on the temperature distributions and heat flux are obtained. The results provide a theory for the increasing crystal growth speed and high quality.
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