3D-Simulation of EFG Process and Deformation of the Growing Silicon Tube

Octagonally shaped silicon tubes are produced at SCHOTT solar by an Edge-defined Film-fed Growth (EFG) technique. The tubes are grown in induction heated EFG furnaces. For this process we developed a coupled thermal-electromagnetic 3D FE-model which serves for analyzing the influences of process parameters and of geometrical shape of components on the distribution of Joule heat and temperature. The calculated temperature distribution in the silicon tube is further coupled to mechanical FE-simulation of stresses, strains, dislocation density and undulation of the tube faces. The investigations aim at the detailed understanding of the process, the improvement of thickness homogeneity, and reduction of stress and deformation of the tube to improve the production yield and the material properties of EFG-wafers