0000000000416657
AUTHOR
Wilfried Von Dr Ammon
Physical modelling of the melt flow during large-diameter silicon single crystal growth
Abstract The reported investigations concern physical modelling of Czochralski growth of silicon large-diameter single crystals. InGaSn eutectic was used as a modelling liquid, employing actual criteria of the real process (Prandtl, Reynolds, Grashof numbers, etc.) and geometric similarity. A multi-channel measuring system was used to collect and process the temperature and flow velocity data. The investigations were focused on the study of heat transfer, in particular, the instability of the “cold zone” of the melt at the crystallization front.
Numerical model of turbulent CZ melt flow in the presence of AC and CUSP magnetic fields and its verification in a laboratory facility
The paper describes a numerical simulation tool for heat and mass transfer processes in large diameter CZ crucibles under the influence of several non-rotating AC and CUSP magnetic fields. Such fields are expected to provide an additional means to influence the melt behaviour, particularly in the industrial growth of large diameter silicon crystals. The simulation tool is based on axisymmetric 2D models for the AC and CUSP magnetic fields in the whole CZ facility and turbulent hydrodynamics, temperature and mass transport in the melt under the influence of the electromagnetic fields. The simulation tool is verified by comparisons to experimental results from a laboratory CZ setup with eutec…
Stress-induced dislocation generation in large FZ- and CZ-silicon single crystals—numerical model and qualitative considerations
When growing silicon crystals with higher diameter (presently up to 300 mm) the thermal stresses and possible dislocation generation in single crystals become a serious problem for both FZ- and CZ-methods. A two-dimensional problem oriented code for the FEM-package ANSYS has been developed to calculate the temperature field in the growing crystal considering radiation exchange with reflectors and environment and thermal stresses. Comparing calculated stresses with critical stresses, the dislocated zone is determined. A qualitative concept for the occurrence of dislocations using the metastable state is developed. In a parametric study for different thermal boundary conditions and crystal ge…