Title: Use of an axial magnetic field to suppress convection in the solvent of Ge_0.98Si_0.02 grown by the travelling solvent method

Authors: L. Abidi, M.Z. Saghir, D. Labrie

Addresses: Ryerson University, Department of Mechanical and Industrial Engineering, 350 Victoria St, Toronto, ON, M5B 2K3, Canada. ' Ryerson University, Department of Mechanical and Industrial Engineering, 350 Victoria St, Toronto, ON, M5B 2K3, Canada. ' Dalhousie University, Department of Physics and Atmospheric Science, Halifax, N.S., B3H 3J5, Canada

Abstract: A three dimensional numerical simulation of the effect of an axial magnetic field on the fluid flow, heat and mass transfer within the solvent of Ge_0.98Si_0.02 grown by the travelling solvent method is presented. The feed rod consists of a Ge_0.85Si_0.15 polycrystalline material, a Ge_0.98Si_0.02 rod which acts as the solvent and a germanium seed located at the bottom of the sample. It is found that a strong convective flow exists in the solvent, which is known to be undesirable to achieve a uniform crystal. An external axial magnetic field is applied to suppress this convection. By increasing the magnetic induction it is observed that the intensity of the flow at the centre of the crucible reduces at a faster rate than near the wall. This phenomenon creates a stable and flat growth interface and the silicon distribution in the horizontal plane becomes relatively homocentric. The maximum velocity is found to obey a logarithmic law with respect to the Hartmann number U_max ∝ H_a^-7/4.

Keywords: crystal growth; dissolution interface; GeSi crystals; growth interface; magnetic field; travelling solvent method; simulation; axial magnetic field; fluid flow; heat transfer; mass transfer.

DOI: 10.1504/IJMPT.2005.005744

International Journal of Materials and Product Technology, 2005 Vol.22 No.1/2/3, pp.2 - 19

Published online: 30 Nov 2004 *

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