Three-dimensional numerical simulation of crystal and crucible rotations during Czochralski growth of Ge_xSi_{1-x} single crystals

Abstract

The influence of crystal and crucible rotations on the flow field and the radial segregation of silicon are predicted during the growth of Ge x Si 1−x crystals by the Czochralski method under microgravity conditions. Time-dependent 3-dimensional numerical simulations are carried out to present the influence of several rotation rates on the radial segregation and flow fields during the growth of Gex Si 1−x . Thermal and solutal Marangoni convection are also considered during this study. Different crystal rotation rates varying between 0 and 30 rpm and stationary or -2 rpm crucible rotation rates are considered. The results show that the crystal and crucible rotation rates have significant influence on the flow field and radial segregation. It is clear that crystal and crucible rotations with an optimum rotation rate lead to good mixing along the growth interface and result in a crystal with a uniform concentration distribution.