BARIUM DOPING OF MOLTEN SILICON FOR USE IN CRYSTAL GROWING PROCESS

• Main Authors: HOLDER, JOHN, D, PHILLIPS, RICHARD, J, KELTNER, STEVEN, J
• Format: Patent
• Language: English; French; German
• Published: 01.10.2003
• Edition: 7
• 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

A process for preparing doped molten silicon for use in a single silicon crystal growing process is disclosed. Polysilicon is doped with barium and melted in a silica crucible containing less than about 0.5% gases insoluble in silicon. During melting and throughout the crystal growing process the barium acts as a devitrification promoter and creates a layer of devitrified silica on the inside crucible surface in contact with the melt resulting in a lower level of contaminants in the melt and grown crystal.