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:
Dec. 25, 1990
Filed:
Jun. 01, 1989
Mitsubishi Metal Corporation, Tokyo, JP;
Abstract
In a method for pulling a single crystal, employing a double crucible assembly, the dopant concentration of the molten raw material in an inner crucible prior to the pulling, is raised to a value higher than the dopant concentration C of the molten raw material in the inner crucible at the steady state. Furthermore, at the initial stage of the pulling, the raw material having a dopant content ratio of no greater than kC is introduced into the outer crucible at a rate greater than the rate of decrease of the molten raw material within the inner crucible during the pulling, to achieve a concentration ratio of dopant between the inner and outer crucibles at a target value. Subsequently, the raw material having kC as the dopant content ratio is introduced into the outer crucible, at a rate equal to the rate of decrease of the molten raw material during the pulling.