A numerical study of the effects of electromagnetic stirring on the distributions of temperature and oxygen concentration in silicon double-crucible Czochralski processing

The effect of providing electromagnetic stirring of the melt contained in the double crucible in continuous Czochralski method was explored by a mathematical model. It was found that the surface temperature of the melt in the annular region was significantly increased by the stirring, which is quite beneficial for melting the solid feed material, and that the stirring could decrease the oxygen concentration at the crystal/melt interface. Moreover, a multiturned coils system in each phase current was found to be more efficient for driving the convection than the single-turned coils system. The multiturned coils system showed that the temperature increase at the melt surface in the annular region became saturated when the current frequency was very high. Moreover, the oxygen concentration at the melt/crystal interface had a minimum value as the frequency was increased. Electromagnetic stirring may make very positive contributions to the performance of the continuous Czochralski system.