Optimization of Thermal Stresses During Czochralski Growth of Oxides and Halides

ABSTRACT Numerical modeling is an essential tool for evaluating heat transfer phenomena in crystal growth processes. In the present work, a design optimization study is conducted to assess the thermally induced stress within the crystal during Czochralski growth, which drives dislocation multiplication and consequently degrades crystal quality. The parametric study is based on an experimentally validated model setup for CsI, where a new local model is introduced to extrapolate the 2D axisymmetric global temperature field to 3D anisotropic thermal stress calculation for the crystal. The investigated design parameters include different geometric properties for the heat shield, top susceptor and the inductive heater and also crucible materials. The impact of those components is evaluated and combined into an optimized setup, where it is shown that it reduces the stress in the CsI crystal by a factor of 3.7. The geometry of optimized model experiment setup is then applied to calculate thermal stress for oxide materials, such as and .