Ordered structure in non-axisymmetric flow of silicon melt convection

This paper describes the three-dimensional non-axisymmetric flow of a silicon melt in a silicon Czochralski system. A stable vortex with almost the same angular velocity as the crucible is observed by in-situ detection of silicon melt convection using double X-ray radiography. To determine the flow structure in detail, three-dimensional numerical simulation is also carried out for the same geometry; this gives both the three-dimensional temperature and the velocity fields. The simulation predicts a stable vortex rotating with the crucible. The temperature field is also modulated in the azimuthal direction due to the stable vortex. The results of the experiments and numerical simulation show that the non-axisymmetric flow is due to a baroclinic instability.