Imaging of convection in a Czochralski crucible under ultrasound waves

The influence of ultrasound on natural and forced convection in a Czochralski crucible was investigated experimentally. We present a method for simulation of ultrasound influence on convection in the melt during Czochralski growth. Distilled water is used as model fluid contained in a stainless-steel crucible with two glass windows. An aluminum cylinder is used to simulate the growing crystal. Flow and standing waves visualization and flow velocity measurements were performed. We report the flow patterns observed under ultrasound influence at frequencies of 0.6 and 1.25 MHz in the fluid for different conditions: temperature difference, cylinder rotation and fluid depth. (C) 2003 Elsevier B.V. All rights reserved.