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:
Jan. 14, 2003
Filed:
Oct. 23, 2001
Koji Kitagawa, Fukushima, JP;
Susumu Sonokawa, Fukushima, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
The present invention provides a method for producing a silicon single crystal by the CZ method, in which a seed crystal having a pointed tip end or truncated pointed tip end shape as a shape of its tip end portion to be brought into contact with a silicon melt is used, the tip end of the seed crystal is carefully brought into contact with the silicon melt, then the seed crystal is descended at a low speed or a surface of the silicon melt is ascended at a low speed to melt the tip end portion of the seed crystal to a desired diameter, and subsequently the seed crystal is slowly ascended or the surface of the silicon melt is slowly descended to grow a silicon single crystal ingot without performing necking, wherein after the tip end of the seed crystal is carefully brought into contact with the silicon melt, the seed crystal is maintained at that state for 5 minutes or more to reserve heat in the seed crystal. Thus, there is provided a method for dislocation-free seeding, which improves a success ratio in making a crystal dislocation-free and enables safe and efficient production of single crystals having a large diameter and a heavy weight at low cost.