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. 04, 2000
Filed:
Dec. 22, 1997
Kazuhiro Matsumoto, Suwa, JP;
Kazuhiko Okawa, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
An object is to realize a protection circuit for protecting a semiconductor device from an ESD or other surge, said protection circuit having its improved reliability with a reduced scale of circuit. An n-type diffusion region (second diffusion region) is formed on a p-type well. A diode D1 formed by the n-type diffusion region and p-type well is connected to the gate electrode of n-type transistor. Thus, the potential difference between a channel region and the gate electrode is reduced to protect the gate oxide film. The n-type diffusion region is formed in the region of the gate electrode on the side of a source region between the source region and a p-type diffusion region (second diffusion region). The layout is determined such that a bipolar formed by the drain region, p-type well and n-type diffusion region will not be turned on. A single contact of minimum size is formed in the n-type diffusion region. When it is desired to form a silicide film, it may not overlap a device isolation film. The present invention may be applied to an output buffer, input buffer, input/output buffer, interface circuit between circuits operable in different power-supply systems or the like.