CdTe crystal growth process by the Bridgman method: numerical simulation

Numerical simulation of the CdTe crystal growth process by the Bridgman met hod is made by using the commercial computational code FLUENT for the mathe matical solution of the governing equations. To reduce computational effort , we have made use of a two level strategy. In the first level we have cons idered the whole system formed by the ampoule with the liquid-solid charge, the furnace, and the air between them. The heat transfer is assumed to occ ur by conduction, convection and radiation between the furnace and the ampo ule, and only by conduction through the ampoule wall and the solid and liqu id CdTe. In the second level we focus on the ampoule and its content, using the values of the temperature field that were calculated in the first leve l as thermal boundary conditions at the ampoule wall. Heat transfer through CdTe is described at this level by conduction and convection. The phase ch ange has been modeled using an enthalpy-porosity formulation. The calculati on of the growth rate at the beginning of the growth shows that this growth rate can be very different from the ampoule translation rate, depending on geometrical and thermal conditions. We analyse the growth rate, axial temp erature gradient, concavity of liquid/solid interface and convective flow f ield in the melt corresponding to the use of ampoules with two different ti p geometries (conical and flat) and three graphite cover thicknesses. (C) 2 001 Elsevier Science B.V. All rights reserved.