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. 03, 1998
Filed:
Apr. 04, 1996
Norihisa Machida, Saitama-ken, JP;
Hisashi Furuya, Tokyo, JP;
Mistsubishi Material Corporation, Tokyo, JP;
Mitsubishi Materials Silicon Corporation, Tokyo, JP;
Abstract
Thermal stress at a point portion of a seed crystal generated when the seed crystal is brought into contact with molten silicon liquid is relieved, thereby to prevent generation of dislocation, to curtail the time of a seed contraction process and to surely support a heavy weight single crystal. A seed crystal of a silicon single crystal used when the single crystal is grown from molten silicon liquid by a Czochralski method is formed to show the heat emissivity of 0.5 or higher and lower than 1.0 at the point portion of the seed crystal. The point portion of the seed crystal is either a part or the whole of the portion that makes contact with the molten silicon liquid or a portion that makes contact with the molten silicon liquid and a portion that makes no contact with the molten silicon liquid in the vicinity of that portion. It is desirable to form at least 16 lines per 1 cm.sup.2 of fine grooves each having a width of 0.3 to 1.0 mm on the surface of the point portion of the seed crystal, to form microscopic irregularity on the surface of the point portion by sandblasting the surface of the point portion of the seed crystal, or to form a SiO.sub.2 film on the surface of the point portion by applying oxidizing treatment to the surface of the point portion of the seed crystal.