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:
Jun. 25, 2002
Filed:
Apr. 12, 2001
Applicant:
Inventors:
Robert J. Falster, Milan, IT;
Joseph C. Holzer, St. Charles, MO (US);
Assignee:
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C30B 1/514 ;
U.S. Cl.
CPC ...
C30B 1/514 ;
Abstract
The present invention relates to single crystal silicon, in ingot or wafer form, which contains an axially symmetric region which is free of agglomerated intrinsic point defects, and a process for the preparation thereof. The process including controlling growth conditions, such as growth velocity, v, instantaneous axial temperature gradient, G , and the cooling rate, within a range of temperatures at which silicon self-interstitials are mobile, in order to prevent the formation of these agglomerated defects. The control of G is accomplished by controlling heat transfer at the melt/solid interface.