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:
Feb. 05, 2008
Filed:
Aug. 13, 2004
Izumi Fusegawa, Nishishirakawa-gun, JP;
Nobuaki Mitamura, Nishishirakawa-gun, JP;
Takahiro Yanagimachi, Nishishirakawa-gun, JP;
Izumi Fusegawa, Nishishirakawa-gun, JP;
Nobuaki Mitamura, Nishishirakawa-gun, JP;
Takahiro Yanagimachi, Nishishirakawa-gun, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
The present invention is a method for producing a single crystal in accordance with Czochralski method by flowing an inert gas downward in a chamberof a single crystal-pulling apparatusand surrounding a single crystalpulled from a raw material meltwith a gas flow-guide cylinder, wherein when a single crystal within N region outside OSF region generated in a ring shape in the radial direction of the single crystal is pulled, the single crystal within N region is pulled in a condition that flow amount of the inert gas between the single crystal and the gas flow-guide cylinder is 0.6 D(L/min) or more and pressure in the chamber is 0.6 D(hPa) or less, in which D (mm) is a diameter of the single crystal to be pulled. It is preferable that there is used the gas flow-guide cylinder that Fe concentration is 0.05 ppm or less, at least, in a surface thereof. Thereby, there is provided a method for producing a single crystal, wherein in the case that a single crystal is produced by an apparatus having a gas flow-guide cylinder in accordance with CZ method, the single crystal has low defect density and Fe concentration can be suppressed to be 1×10atoms/cmor less even in a peripheral part thereof.