MODELING OF THERMAL FLUID-FLOW IN THE LIQUID ENCAPSULATED CZOCHRALSKIPROCESS AND COMPARISON WITH EXPERIMENTS

The thermal fluid flow in liquid encapsulated Czochralski (LEC) proces s has been studied by a combined experimental and numerical modelling approach. Experiments using gallium melt and a stationary dummy crysta l have been performed in an industrial puller with the crucible rotati ng at 30 rpm. This system is numerically simulated by a global conduct ion-radiation and a three-dimensional (3D) melt convection model. Sign ificant difference in thermal fluid flow structures is found depending on the crucible position. This illustrates the strong influence of th e thermal boundary conditions on the fluid flow. From practical viewpo int, it is therefore important to optimize the crucible, i.e. the grow th position in the LEC process.