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:
Nov. 25, 2003
Filed:
Sep. 30, 2002
Applicant:
Inventors:
Assignee:
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C30B 1/500 ;
U.S. Cl.
CPC ...
C30B 1/500 ;
Abstract
A process for growing a single crystal silicon ingot having an axially symmetric region substantially free of agglomerated intrinsic point defects. The ingot is grown generally in accordance with the Czochralski method; however, the manner by which the ingot is cooled from the temperature of solidification to a temperature which is in excess of about 900° C. is controlled to allow for the diffusion of intrinsic point defects, such that agglomerated defects do not form in this axially symmetric region. Accordingly, the ratio v/G is allowed to vary axially within this region, due to changes in v or G , between a minimum and maximum value by at least 5%.