Novel method for melt flow control in unidirectional solidification of multi-crystalline silicon

Based on numerical modeling, a novel method for melt stirring in the directional solidification method of multicrystalline silicon is proposed. It consists of two electrodes in contact with the free melt surface. The whole melt is placed in a low intensity vertical magnetic field and an electrical DC current passes through the electrodes. It was found that even a small magnetic field (10 mT) and an electrical current in electrodes of max 10 A can produce a significant stirring effect. The melt stirring is expected to influence the dopant and impurities distribution in a beneficial way. The influence of melt stirring on the interface shape was also studied and it was found that large currents (5–10 A) make a significant impact on interface shape, but small values of electrical current (2 A) can be beneficial for interface shape and deflection.

► A novel method for melt stirring in unidirectional solidification of m-c silicon is proposed.
► A combination of vertical magnetic field and an electrical current was considered.
► Small values of magnetic field (10 mT) and electrical current (2–10 A) generate a stirring effect.
► The melt flow patterns depend on the electrodes positions at the melt free surface.
► The method can provide additional parameter to control the melt flow and interface shape.