Effects of Rotation on Heat Flow, Segregation, and Zone Shape in a Small-scale Floating-zone Silicon Growth under Axial and Transversal Magnetic Fields

Abstract

The suppression of unstable Marangoni convection in floating-zone crystal growth by magnetic fields has enjoyedover recent years a widespread use as a reliableand useful strategy. A transversal directionof the field is particularly efficient, but asymmetric zone shapes and thussegregation are induced. Counter-rotationof the feed and of the crystal rods is a common way to improve dopant homogeneity. However, its effects under mag- netic fields are complex and have not yet been studied in detail. In the present analysis, three-dimensional (3D) simulations based on a finite-volume/multigrid method are used to illustrate the effects of rotation on the heat flow, dopant segregation, and the zone shape for a small- scale floating-zone silicon growth under both axial and transversal magnetic fields. The role of electrical con- ductivity of the crystal is also taken into account. keyword: Rotation, Convection, Segregation, Mag- netic field, Lorentz force, Floating-zone method.