Numerical Simulation on Design of Temperature Control for Side Heater in Directional Solidification System of Multi-Crystalline Silicon

In this paper, the transient numerical simulation was used to study the effects of temperature variation in three ways (the open downward parabola, the straight line and the open upward parabola) of side heater in multi-crystalline silicon directional solidification system during solidification period. The melt-crystal (m/c) interface, thermal field and thermal stress during directional solidification of polysilicon have been simulated. The results show that in the process of solidification, compared with the open downward parabola and straight line temperature variation, the temperature change of the side heater depends on the open upward parabola can better control the horizontal and vertical temperature difference in polysilicon, making the deflection of m/c interfaces smaller. Smaller thermal stress distribution can be obtained from the middle stage to the end of solidification while temperature change of side heater according to upward parabola, which is beneficial to improve the quality of polysilicon ingots.