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:
Mar. 02, 1999
Filed:
Dec. 15, 1997
Komatsu Electronic Metals Co., Ltd., Kanagawa, JP;
Abstract
This invention provides a method for pulling a single crystal silicon whose diameter is more than 200 mm. The single crystal silicon pulled by the method of this invention has a desired oxygen concentration and a uniform oxygen concentration distribution along its longitudinal axis. In the process of this invention, the single crystal silicon and the quartz crucible are driven to rotate in reverse directions, and the rotation speed of the single crystal silicon is set within the range of 8 to 16 rpm and to be more than twice the rotating speed of the crucible. The rotation speed of the crucible is set to be at its minimum value during pulling a body portion which begins from the beginning end of the single-crystal body and terminates at a location apart from the beginning end within a distance of 10% of the total length of the single-crystal body. Subsequently, the rotation speed of the crucible is gradually raised and is set to no more than a maximum value of 8 rpm.