Modeling The Solute Segregation In Vertical Bridgman Growth By Using Free-Surface Technique

In this paper, the solute segregation in vertical Bridgman growth of semiconductor diluted alloys is studied by using numerical simulation. The purpose of this work is the 2D axi-symmetric modeling of the transient solidification process of these crystals. The full problem of heat transfer, hydrodynamics and solute conservation is studied with the finite element software FIDAP (TM). To get a more realistic description of time-dependent solidification process we employ the free-surface model for the solid/liquid interface. The dimensionless forms of the governing equations are used in order to avoid the difficulties related to numerical convergence. We discuss the compatibility between the two forms of non-dimensional equations implemented in the software, in the conditions of using the free-surface enhancements introduced by the new version of FIDAP 8.5. The results of our simulation for axial and radial segregation are compared to the experimental data and to the predictions of analytical models. The difficulties related to modeling the solute segregation in the transient process are discussed.