Graph of enthalpy (top) and convection in the melt (bottom) for three different times of the simulation.
Single crystals of (Cd,Zn)Te are an excellent substrate material for epitaxial growth of (Hg,Cd)Te layers and are usually grown by the vertical Bridgman method. We present a simulation of the whole growth process in two steps: In the first step, the (stationary) heat transport in the furnace is modeled and calculated for different positions of the ampoule. This gives information about the most important parameter during this process: the temperature distribution in furnace and ampoule. The obtained temperatures are then used in the second step as boundary conditions for the (time dependent) simulation of temperature and convection in the ampoule. For the discretization of the convection in the melt, a penalty method for treating parabolic problems on time dependent domains is presented. Only the use of adaptive finite element methods allows an efficient numerical simulation of the moving phase boundary, the convection in the melt and the temperature distribution in melt and crystal. Numerical results are presented for both furnace and ampoule simulation.
Key words. Crystal growth, phase transition, Navier-Stokes on time dependent domains, adaptive finite elements