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:
Apr. 06, 1999
Filed:
Sep. 03, 1996
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A semiconductor memory device is provided which comprises: a plurality of memory cell transistors each having a tunnel oxide film formed on a semiconductor substrate of a first conductivity type, a floating gate formed on the tunnel oxide film, a control gate overlaid on the floating gate with intervention of an insulating film, source/drain regions of a second conductivity type formed in the semiconductor substrate, and a high-concentration impurity layer of the first conductivity type formed in a portion adjacent to the drain region below the floating gate by oblique ion implantation employing an implantation angle .theta. with respect to a normal line to the semiconductor substrate; the plurality of memory cell transistors each sharing a source region with a memory cell transistor disposed adjacent thereto on one side thereof and a drain region with a memory cell transistor disposed adjacent thereto on the other side thereof; the implantation angle .theta. being defined by the following expression: