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:
Jul. 09, 2002
Filed:
Oct. 13, 1999
Robert J. Falster, London, GB;
Martin Jeffrey Binns, St. Charles, MO (US);
Alan Wang, O'Fallon, MO (US);
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Abstract
A single crystal silicon wafer having a central axis, a front side and a back side which are generally perpendicular to the central axis, a central plane between the front and back sides, a circumferential edge, and a radius extending from the central axis to the circumferential edge. The wafer comprises first and second axially symmetric regions. The first axially symmetric region extends radially inwardly from the circumferential edge, contains silicon self-interstitials as the predominant intrinsic point defect, and is substantially free of agglomerated interstitial defects. The second axially symmetric region has vacancies as the predominant intrinsic point defect, comprises a surface layer extending from the front side toward the central plane and a bulk layer extending from the surface layer to the central plane, wherein the number density of agglomerated vacancy defects present in the surface layer is less than the concentration in the bulk layer.