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. 19, 1989
Filed:
Jul. 08, 1988
Yutaka Hayashi, Tsukuba, JP;
Itsunari Hayabuchi, Yokohama, JP;
Tatsuo Tsuchiya, Kawagoe, JP;
Seiichi Ishihara, Sayama, JP;
Director General of Agency of Industrial Science and Technology, Tokyo, JP;
Research Development Corporation of Japan, Tokyo, JP;
Citizen Watch Co., Ltd., Tokyo, JP;
Abstract
In an MONOS type nonvolatile semiconductor memory comprising a channel forming semiconductor region between source and drain regions in a surface of a substrate; a tunnel insulating film formed on the channel forming semiconductor region in the surface of the substrate, the tunnel insulating film permitting charge-injection; a silicon nitride film formed as a second insulating film on the tunnel insulating film; a silicon oxide film formed as a third insulating film; and a conductive electrode formed on the silicon oxide film, the silicon nitride film has a composition close to a stoichiometric value of Si.sub.3 N.sub.4 at a portion near an interface with the tunnel insulating film and has a composition of excess silicon at a portion of the thickness of the same film except near the interface with the tunnel insulating film.