Combining a rotating magnetic field and crystal rotation in the floating-zone process with a needle-eye induction coil

N. Ma, J. S. Walker, A. Lüdge, H. Riemann

Research output: Contribution to journalConference articlepeer-review

19 Scopus citations

Abstract

This paper presents numerical solutions for the steady, axisymmetric melt motions in a simplified model of the floating-zone process with a needle-eye induction coil. With only buoyant and thermocapillary convections, there are two meridional circulations, and the stronger, outer circulation involves an undesirable radially inward flow near the crystal-melt interface. Adding crystal rotation alone can only decrease the magnitudes of the meridional circulations. Adding a rotating magnetic field alone has the undesirable effect of increasing the magnitude and extent of the radially inward flow near the crystal-melt interface. Combining a rotating magnetic field in one azimuthal direction with crystal rotation in the opposite azimuthal direction overwhelms the buoyant and thermocapillary convections and produces the desired radially outward flow over the entire crystal-melt interface. The magnitude of this radially outward flow is easily controlled by changing either the angular velocity of the crystal rotation or the strength of the rotating magnetic field.

Original languageEnglish
Pages (from-to)118-124
Number of pages7
JournalJournal of Crystal Growth
Volume230
Issue number1-2
DOIs
StatePublished - Aug 2001
Externally publishedYes

Funding

This research was supported by the National Aeronautics and Space Administration under Grants NAG8-1453 and NAG8-1656 and by the University of Missouri Research Board. The calculations were performed on a workstation donated by the International Business Machines Corporation.

FundersFunder number
National Aeronautics and Space AdministrationNAG8-1453, NAG8-1656
University of Missouri

    Keywords

    • A1. Computer simulations
    • A1. Fluid flows
    • A1. Magnetic fields
    • A2. Floating zone technique
    • B2. Semiconducting silicon

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