Influence of Thermal Processing Parameters and Material Properties on Velocity Configurations in Semiconductor Melts During the Vertical Bridgman Growth Technique

The paper deals with the influence of thermal boundary conditions and thermophysical material properties on velocity configurations in Bridgman arrangements. Numerical simulations are presented for (Bi_1—xSb_x)₂Te₃ melts as a representative for semiconductor melts of low Prandtl numbers. Based on two characteristic temperature profiles, results have been calculated for 2D-axisymmetric and 3D Bridgman configurations applying the FIDAP^TM FEM code using pseudo-steady-state conditions with a constant growth rate. For simulation close to real growth conditions the model used includes real geometry parameters as well as the experimentally measured temperature distribution at the outer ampoule surface and temperature depending material properties. The calculations show significant variations in the flow configuration and the resulting radial inhomogeneity of the grown crystal depending on the thermal processing parameters used.