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:
May. 27, 2003
Filed:
Dec. 18, 2001
Applicant:
Inventors:
Hiroki Murakami, Saga, JP;
Kazuyuki Egashira, Saga, JP;
Assignee:
Sumitomo Metal Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C30B 1/520 ;
U.S. Cl.
CPC ...
C30B 1/520 ;
Abstract
A silicon wafer characterized in that the laser scattering tomography defect occurrence region accounts for at least 80% of the wafer surface area and that the laser scattering tomography defects have a mean size of not more than 0.1 &mgr;m, with the density of those defects which exceed 0.1 &mgr;m in size being not more than 1×10 cm , and wafers derived from this wafer as the raw material by heat treatment for oxide precipitate formation, by heat treatment for denuded layer formation or by epitaxial layer formation on the surface are useful as semiconductor materials.