Effects of Induced Current in Crystals on the Melt Flow and the Melt–Crystal Interface during Industrial 300 mm Czochralski Silicon Crystal Growth under a Transverse Magnetic Field

Abstract

Due to the high magnetic field intensity during industrial 300 mm silicon crystal growth, typically up to 0.3 T, the crystal's rotation under this transverse magnetic field (TMF) induces a current that is strong enough to impact both the melt flow and the melt/crystal interface (m/c interface) shape. This paper investigates the influence of TMF-induced current in crystals on the melt flow, temperature distribution, and interface shape through the conduction of three sets of 3D simulations that vary in the electrical conductivity of crystals, TMF intensities, and crystal rotation rates. Combined with experiments, the accuracy of the model has been validated, and a reasonable electrical conductivity of the crystal has been predicted. The study findings reveal a shift in the driving force of forced convection from centrifugal to Lorentz force when the induced current in crystal is augmented. This alteration affects the melt flow and the m/c interface shape. Notably, this study serves as a significant complement to the conventional model, which overlooks the induced current in crystals, enhancing the accuracy and comprehensiveness of the simulation outcomes to provide a robust theoretical underpinning for industrial production.

Modelling and Control of Thermal Stress in TSLAG (Tb3Sc1.95Lu0.05Al3O12) Magneto-Optical Crystals Grown by Czochralski Method

“…Conversely, it is evident that as the crystal rotation speed increases, the melt velocity beneath the crystal increases, and the clockwise flow strengthens, manifested by the expansion of its occupied area. In should be pointed out that the clockwise flow beneath the crystal hinders the attainment of a flat c-m interface [16]. Therefore, the improvement in crystal speed is not conducive to obtaining a flat c-m interface in the present study.…”