Premium
Numerical analysis of the influence of ultrasonic vibration on crystallization processes
Author(s) -
Ubbenjans B.,
FrankRotsch Ch.,
Virbulis J.,
Nacke B.,
Rudolph P.
Publication year - 2012
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201100413
Subject(s) - materials science , diffusion , crystallization , crystal (programming language) , ultrasonic sensor , crucible (geodemography) , mechanics , boundary layer , fluent , convection , instability , diffusion layer , displacement (psychology) , mass transfer , phase (matter) , fluid dynamics , computer simulation , layer (electronics) , composite material , acoustics , thermodynamics , chemistry , physics , computer science , psychology , computational chemistry , organic chemistry , psychotherapist , programming language
The challenge in the future fabrication of semiconductor bulk crystals is the improvement of the crystal quality with a simultaneous increase of the yield. For that, a proper control of mass transfer within the fluid phase is required. Besides the damping of violent convective fluctuations, the thickness of the diffusion boundary layer, causing morphological instability, has to be decreased. The influence of ultrasound in molten Germanium was analyzed by numerical simulations. The simulations were provided by applying commercial software packages ANSYS ® and FLUENT ® . ANSYS ® was used to model the ultrasonic wave propagation in the whole growth system consisting of melt and crystal, crucible and surrounding media. As a result the sound pressure distribution in every point of the melt and the displacement in every point of the solid have been obtained. The melt flow and the temperature distribution were simulated with the help of FLUENT ® . The main focus was the analysis of Schlichting streams that occur at the crystallization front which affect the diffusion boundary layer. It was shown that ultrasonic treatment can help to reduce the harmful diffusion boundary layer very effectively. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)