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. 29, 2010
Filed:
Oct. 10, 2007
Atsuhiro Sato, Yokohama, JP;
Fumitaka Arai, Yokohama, JP;
Yasuhiko Matsunaga, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A nonvolatile semiconductor memory of an aspect of the present invention comprises a plurality of memory cell transistors which are connected in series to one another with a first gate spacing, every two adjacent transistors of the memory cell transistors sharing a source/drain diffusion layer, and a first select gate transistor which shares a source/drain diffusion layer with an endmost memory cell transistor that is located at one end of the series connection of the memory cell transistors and is adjacent to that memory cell transistor with a second gate spacing. The second gate spacing is set larger than the first gate spacing and the source/drain diffusion layer shared by the endmost memory cell transistor and the first select gate transistor contains a region which is higher in impurity concentration than the source/drain diffusion layer shared by two adjacent memory cell transistors.