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:
Sep. 01, 2009
Filed:
Jun. 13, 2006
Yutaka Kishida, Chiba, JP;
Seiki Takebayashi, Chiba, JP;
Teruyuki Tamaki, Chiba, JP;
Siltronic AG, Munich, DE;
Abstract
In silicon single crystal growth by the Czochralski method using a quartz crucible, a silicon single crystals with a uniform distribution of oxygen concentration can be produced in high yield without being affected by changes of crystal diameter and initial amount of melt feedstock. The oxygen concentration is adjusted by estimating oxygen concentration during growth on the basis of a relationship among three parameters: crucible rotation rate (Ω), crucible temperature (T), and the ratio (β) of contact area of molten silicon with the inner wall of the crucible and with atmospheric gas, and by associating the temperature (T) with the ratio (β) by the function 1/β×Exp(−E/T) where E is the dissolution energy (E) of quartz into molten silicon to control at least one of the rotation rate (Ω) and temperature (T) to conform the estimated oxygen concentration to a target concentration.