Modified FZ technique for oxides crystal growth

Abstract

The crucibleless AHP (axial heat flux close to the phase interface) method for growing single crystals of oxides is proposed. The phenomena of wetting and meniscus shaping are considered for the case when a melt from the top of the submerged heater to its bottom close to the melt-crystal interface gets mostly due to the presence of a capillary through-hole in the center of its casing made of noble metal. Both analytical and numerical approaches are applied, in order to describe conditions of the experiment preparation before the solidification process.Based on the example of TeO2, steady-state meniscus stability, as well as the melt flow dynamics in process are considered in the paper. The mathematical 2D axisymmetric model taken into account continuity equation, laminar flow (Navier-Stokes), including surface tension effects, the equation for the transport of the fluid interface. The Level Set Method implemented for a two-phase gas-liquid domain allows the smooth variation of density and dynamic viscosity across this interface. The numerical calculations, from one hand, make it possible to estimate the appropriate value of the heater height, as well as relations of the translating rate for top and bottom rods to provide the modes of enlarged and constant diameter during the crystal growth. The last is very important from the point of view of the process control being the additional feedback parameters to be used in control loop of charge melt feeding.