Simplified numerical approach for estimation of effective segregation coefficient at the melt/crystal interface

•A thermal gravitational convection was investigated for a Bridgman technique in microgravity.•The equations were calculated in the coordinate system moving with melt/crystal interface.•The dependence of effective segregation coefficient Keff was studied upon microgravity and ampoule sizes.•The resulting dependences were presented as Keff upon Vmax—maximum value of velocity magnitude.•These dependences were compared with the data of semi-analytical and analytical models.

A thermo-gravitational convection and impurity transfer in the melt were investigated using a simplified numerical model for Bridgman GaSb(Te) crystal growth in microgravity conditions. Simplifications were as follows: flat melt/crystal interface, fixed melt sizes and only lateral ampoule heating. Calculations were carried out by Ansys®Fluent® code employing a two-dimensional Navier–Stokes–Boussinesq and heat and mass transfer equations in a coordinate system moving with the melt/crystal interface. The parametric dependence of the effective segregation coefficient Keff at the melt/crystal interface was studied for various ampoule sizes and for microgravity conditions. For the uprising one-vortex flow, the resulting dependences were presented as Keff vs. Vmax—the maximum velocity value. These dependences were compared with the formulas by Burton–Prim–Slichter׳s, Ostrogorsky–Muller׳s, as well as with the semi-analytical solutions.