Journal of Crystal Growth 211 (2000) 360 } 364 The in#uence of thermoelectromagnetic convection (TEMC) on the Bridgman growth of semiconductors Serhat Yesilyurt*, Ljubomir Vjusic, Shariar Motakef, F.R. Szofran, Arne Croell Cape Simulations, Inc., One Bridge Street, Newton, MA 02458, USA Marshall Flight Space Center, Huntsville, AL 35812, USA AMMSA, University of Alabama in Huntsville, AL 35803, USA Abstract Application of a low-intensity axial magnetic "eld can promote signi"cant convection during Bridgman growth of GeSi when resident thermoelectric currents at the growth interface are large due to the di!erence of thermoelectric powers of the melt and of the crystal and the tangential temperature gradient at the interface. Thermoelectromagnetic convection (TEMC) in the GeSi melt is characterized by a meridional #ow driven by the rotation of the #uid due to the azimuthal Lorentz force from currents in the radial direction concentrated near the interface and an axial magnetic "eld. In this work, we developed a computational model to study convection of the GeSi melt in varying g and magnetic "eld intensity levels.  2000 Elsevier Science B.V. All rights reserved. Keywords: Thermoelectromagnetic convection; Vertical Bridgman growth 1. Introduction Thermoelectromagnetic convection (TEMC) is based on the principle that thermoelectric currents in a #uid can create a driving force responsible for convection in the presence of an applied magnetic "eld crossing these currents [1]. In any material a temperature gradient, ¹, produces a Seebeck electromotive force S¹ where S is the thermoelec- tric power of the material. If the gradients of S and ¹ are not parallel, then a thermoelectric current is generated in the system. Application of a magnetic * Corresponding author. Tel.: #1-617-796-8882; fax: #1- 617-796-7870. E-mail address: serhat@capesim.com (S. Yesilyurt) "eld to such a system produces a thermoelec- tromagnetic body force, and an associated #ow in the melt. As the applied magnetic "eld is adjusted, TEMC can be controlled, and the buoyancy- induced convection be modi"ed. The necessary and suzcient condition for genera- tion of thermoelectric currents is the presence of nonparallel gradients of S and ¹ [1]. This condi- tion is present in solidi"cation processes under the following circumstances: (1) at the growth interface where the melt and solid have di!erent thermoelec- tric powers, and the solid}melt interface is not isothermal; e.g., pseudo-binaries such as GeSi and HgCdTe where the variation of melt composition at the growth interface results in a nonisothermal surface; (2) at facetted growth interfaces, where the facet undercooling provides the necessary 0022-0248/00/$ - see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 2 - 0 2 4 8 ( 9 9 ) 0 0 8 0 8 - 8