The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 02, 1999
Filed:
Jun. 14, 1995
Richard L Hansen, Cleveland, OH (US);
Larry E Drafall, St. Charles, MO (US);
Robert M McCutchan, St. Louis, MO (US);
John D Holder, St. Louis, MO (US);
Leon A Allen, Grover, MO (US);
Robert D Shelley, Chesterland, OH (US);
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Abstract
A crucible in which a semiconductor material is melted and held during a crystal growing process. The crucible includes a body of vitreous silica having a bottom wall and a sidewall formation extending up from the bottom wall and defining a cavity for holding the molten semiconductor material. The sidewall formation has an inner and an outer surface. A first devitrification promoter on the inner surface of the sidewall formation is distributed such that a first layer of substantially devitrified silica is formed on the inner surface of the crucible which is in contact with the molten semiconductor material when the semiconductor material is melted in the crucible during the crystal growing process. A second devitrification promoter on the outer surface of the sidewall formation is distributed such that a second layer of substantially devitrified silica is formed on the outer surface of the crucible when the semiconductor material is melted in the crucible during the crystal growing process. The first substantially devitrified silica layer is such that it promotes uniform dissolution of the inner surface and in so doing significantly reduces the release of crystalline silica particulates into the molten semiconductor material as a crystal is pulled from the molten semiconductor material. The second substantially devitrified silica layer is such that it reinforces the vitreous silica body.