Three-dimensional numerical simulation of temperature and flow fields in a Czochralski growth of germanium

For a Czochralski growth of Ge crystal, thermal fields have been analysed numerically using the three-dimensional finite volume method (FLUENT package). The arrangement used in a real Czochralski crystal growth lab included a graphite crucible, heat shield, heating device, thermal insulation and chamber including two gas outlets. We have considered two cases for calculations, which are configuration containing (a) only gas and (b) melt and gas, related to initial stages of the growth process (seeding process). It has been assumed that the growth system is in steady state, fluids are incompressible Newtonian fluids and the flow is laminar. It was shown that the thermal field in the growth setup is completely three-dimensional. Especially, the temperature field at the melt free surface has not a uniform radial distribution due to the three-dimensional orientation of Argon flow above it.