INTERFACE SHAPE IN THE VERTICAL BRIDGMAN CONFIGURATION WITH AND WITHOUT THE SUBMERGED HEATER

The shape of the solid-liquid interface in a multi-zone furnace was st udied experimentally and numerically. Gallium-doped germanium single c rystals were grown with and without the submerged heater (SH). With th e SH, the direction of the heat flux was controlled, and the convectiv e heat transfer at the interface was eliminated. As a result, the inte rface becomes convex with respect to the liquid. During growth with th e rotating SH, a natural convection counter-flow is generated by the c entrifugal forces imposed by the rotating heater. This forced flow cau ses vigorous mixing in the melt near the interface which allows signif icantly higher growth rates while maintaining a planar interface.