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. 02, 2008
Filed:
Nov. 21, 2005
Takamitsu Ishihara, Yokohama, JP;
Takamitsu Ishihara, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A semiconductor memory device includes a memory cell which includes a first gate insulation film provided on the semiconductor substrate; a floating gate electrode provided on the first gate insulation film; a second gate insulation film provided on the floating gate electrode; a control gate electrode provided on the second gate insulation film; a source layer and a drain layer that are provided in the semiconductor substrate, the source layer and the drain layer respectively being provided either side of a channel region which is below the floating gate electrode; a source electrode that is electrically connected to the source layer; a buffer film provided on the drain layer; and a memory cell including a drain electrode electrically connected to the drain layer through the buffer film, wherein when viewing the surface of the semiconductor substrate from above, an overlapped area between the floating gate electrode and the drain layer is smaller than an overlapped area between the floating gate electrode and the source layer.