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:
Jul. 21, 1992
Filed:
Nov. 16, 1990
Tetsuhiro Oda, Takefu, JP;
Susumu Sonokawa, Takefu, JP;
Atsushi Ozaki, Annaka, JP;
Toshio Hisaichi, Annaka, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
A method for controlling an oxygen concentration of a single crystal which is pulled up in a Czochralski-method type single crystal pulling apparatus having a hermetical chamber in which the single crystal is pulled up and an inert gas supply and exhaust system by means of which an inert gas is supplied to the hermetical chamber and exhausted therefrom; the method being characterized in that the pneumatic pressure in the hermetical chamber and the supply rate of the inert gas are controlled in accordance with a prepared control pattern with respect to the proportion of the length of the as-grown crystal to the aimed final length thereof or with respect to the passage of time.