METHODS AND SYSTEM FOR GENERATING A PUMPING FORCE IN A SILICON MELT BY APPLYING A TIME-VARYING MAGNETIC FIELD

• Main Authors: SREEDHARAMURTHY, HARIPRASAD, KORB, HAROLD, W, KULKARNI, MILIND, S
• Format: Patent
• Language: English; French; German
• Published: 03.10.2012
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; CHEMISTRY; CRYSTAL GROWTH; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

Controlling crystal growth in a crystal growing system is described. The crystal growing system includes a heated crucible including a semiconductor melt from which a monocrystalline ingot is grown according to a Czochralski and the ingot is grown on a seed crystal pulled from the melt. The method includes applying a cusped magnetic field to the melt by supplying an upper coil with a first direct current (IUDC) and supplying a lower coil with a second direct current (ILDC). The method also includes supplying the upper coil with a first alternating current (IUAC) and supplying the lower coil with a second alternating current (ILAC) to generate a time-varying magnetic field, wherein the time-varying magnetic field generates a pumping force in the semiconductor melt.