CENTRIFUGAL PUMPING DURING CZOCHRALSKI SILICON GROWTH WITH A STRONG TRANSVERSE MAGNETIC-FIELD

During Czochralski silicon growth with a strong, uniform, steady, hori zontal magnetic field, the melt motion driven by the rotations of the crystal and crucible about their common vertical axis is decoupled fro m the buoyant and thermocapillary convections. This paper presents num erical predictions of the rotationally driven radial and axial velocit ies near the crystal-melt interface and near the free surface. The cen trifugal force associated with the azimuthal velocity drives the radia l motion, while the electromagnetic body force opposes melt motions ac ross magnetic field lines. The extremely non-axisymmetric radial motio n involves large velocities parallel to the magnetic field and small v elocities perpendicular to it. While the electrical conductivity of th e solid crystal is small compared to that of the melt, the radial and axial velocities influenced by the conductive crystal are found to be very different from those for an electrically insulating crystal.