Epitaxially coated silicon wafer and method for producing an epitaxially coated silicon wafer

• Main Authors: LAUBE FRANK, PASSEK FRIEDRICH, SCHAUER REINHARD, PICKEL MARTIN
• Format: Patent
• Language: English
• Published: 06.11.2012
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; BASIC ELECTRIC ELEMENTS; CHEMISTRY; CRYSTAL GROWTH; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SEMICONDUCTOR DEVICES; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

Epitaxially coated silicon wafers have a rounded and polished edge region and a region adjacent to the edge having a width of 3 mm on the front and rear sides, a surface roughness in edge region of 0.1-1.5 nm RMS relative to a spatial wavelength range of 10-80 μm, and a variation of surface roughness of 1-10%. The wafer edges, after polishing, are examined for defects and roughness at the edge and surrounding region. Silicon wafers having a surface roughness of less than 1 nm RMS are pretreated in single wafer epitaxy reactors, first in a hydrogen atmosphere at a flow rate of 1-100 slm and in a second step, an etching medium with a flow rate of 0.5-5 slm is conducted onto the edge region of the wafer by a gas distribution device. The wafer is then epitaxially coated.