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. 04, 2001
Filed:
Feb. 16, 1999
Gregory M. Wilson, Chesterfield, MO (US);
Jon A. Rossi, Chesterfield, MO (US);
Charles C. Yang, St. Peters, MO (US);
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Abstract
This invention is directed to a novel a single crystal silicon wafer. The wafer comprises: (a) two major generally parallel surfaces (ie., the front and back surfaces); (b) a central plane between and parallel to the front and back surfaces; (c) a front surface layer which comprises the region of the wafer extending a distance of at least about 10 &mgr;m from the front surface toward the central plane; and (d) a bulk layer which comprises the region of the wafer extending from the central plane to the front surface layer. This wafer is characterized in that the wafer has a non-uniform distribution of crystal lattice vacancies, wherein (a) the concentration of crystal lattice vacancies in the bulk layer are greater than the concentration of crystal lattice vacancies in the front surface layer, (b) the crystal lattice vacancies have a concentration profile in which the peak density of the crystal lattice vacancies is at or near the central plane, and (c) the concentration of crystal lattice vacancies generally decreases from the position of peak density toward the front surface of the wafer. In addition, the front surface of the wafer has an epitaxial layer deposited thereon. The epitaxial layer has an average light scattering event concentration of no greater than about 0.06/cm,as measured by a laser-based auto inspection tool configured to detect light scattering events corresponding to polystyrene spheres having diameters of no less than about 0.12 &mgr;m. The bulk layer comprises voids which are at least about 0.01 &mgr;m in their largest dimension.