Melt motion during liquid-encapsulated Czochralski crystal growth in steady and rotating magnetic fields

Abstract

During the liquid-encapsulated Czochralski (LEC) process, a single compound semiconductor crystal such as gallium-antimonide is grown by the solidification of an initially molten semiconductor (melt) contained in a crucible. The motion of the electrically-conducting molten semiconductor can be controlled with externally-applied magnetic fields. A steady magnetic field provides an electromagnetic stabilization of the melt motion during the LEC process. With a steady axial magnetic field alone, the melt motion produces a radially-inward flow below the crystal–melt interface. Recently, an extremely promising flow phenomenon has been revealed in which a rotating magnetic field induces a radially-inward flow below the crystal–melt interface that may significantly improve the compositional homogeneity in the crystal. This paper presents a model for the melt motion during the LEC process with steady and rotating magnetic fields.