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. 21, 2011
Filed:
Oct. 02, 2007
Timo Müller, Burghausen, DE;
Martin Weber, Kastl, DE;
Gudrun Kissinger, Lebus, DE;
Siltronic AG, Munich, DE;
Abstract
Silicon wafers in the entire volume of which crystal lattice vacancies are the prevalent point defect type, have a rotationally symmetric region whose width is at least 80% of the wafer radius, crystal lattice vacancy agglomerates of at least 30 nm in a density ≦6·10cm, crystal lattice vacancy agglomerates of from 10 nm to 30 nm in a density of 1·10cmto 3·10cm, OSF seeds in a density of 0 to 10 cm, and an average bulk BMD density of 5·10cmto 5·10cm, which varies at most by a factor of 10 radially over the entire silicon wafer, and a BMD-free layer on the front side, wherein the first BMD is found at a depth of at least 5 μm and on average at a depth of at least 8 μm.