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:
Mar. 26, 2002
Filed:
Aug. 27, 1999
Robert J. Falster, Milan, IT;
Martin Jeffrey Binns, St. Charles, MO (US);
Harold W. Korb, Town & Country, MO (US);
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Abstract
A process for heat-treating a single crystal silicon wafer to dissolve agglomerated vacancy defects and to influence the precipitation behavior of oxygen in the wafer in a subsequent thermal processing step is disclosed. The wafer has a front surface, a back surface, and a central plane between the front and back surfaces. In the process, the wafer is subjected to a thermal anneal to dissolve agglomerated vacancy defects present in a stratum extending from the front surface toward the center of the wafer. The annealed wafer is then heat-treated to form crystal lattice vacancies, the vacancies being formed in the bulk of the silicon. The heat-treated wafer is cooled from the temperature of said heat treatment at a rate which allows some, but not all, of the crystal lattice vacancies to diffuse to the front surface to produce a wafer having a vacancy concentration profile in which the peak density is at or near the central plane with the concentration generally decreasing in the direction of the front surface of the wafer.