The concentration profile of impurities in the Czochralski liquid metal under the rotational magnetic field.

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The single crystal of silicon is mainly manufactured by the Czochralski growing method from the molten silicon whose convection has been considered to be responsible for the quality of the single crystals. This study is our trial to employ a rotating magnetic field for liquid metal of Czochralski type configuration.In the experiment, Gallium melt (melting point, 303K) was used for the experimental fluid. A glass crucible is employed with its inner diameter 46 mm, in which gallium is filled at 45 mm high. The bottom plane of cooling rod is attached to the surface of gallium melt and the side and bottom walls of crucible were heated. The horizontal and the rotational magnetic field apply to the ocillating melt flow in the Czochralski configulation. As the results,1)The oscillation periods in the temperature differed under the horizontal and rotational magnetic field for the same magnetic intensity.2)The oscillation period under the rotational magnetic field decreased remarkably than the horizontal magnetic field.3)The oscillation period under the rotational magnetic field decreased with the magnetic flux density but increased for the horizontal magnetic field.The numerical computation carried out for the concentration profile of impurities in the Czochralski liquid metal under the rotational magnetic field. The average concentration at the crystal-melt interface decreasing with increasing the magnetic flux density and the rotional rates of magnetic field.