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:
Mar. 09, 1999
Filed:
Sep. 30, 1997
Shigeru Nagatomo, Miyazaki, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
A protection circuit for a semiconductor device, the protection circuit being connected an input terminal of the semiconductor device in parallel with an internal circuit proper of the semiconductor device, comprising a semiconductor substrate having one conductivity, a first diffusion layer having the other conductivity produced along the top surface of the semiconductor substrate, a second diffusion layer having the other conductivity produced along the top surface of the first diffusion layer, the impurity concentration of the second diffusion layer being larger than that of the first diffusion layer, at least one third diffusion layer having one conductivity produced along the top surface of the semiconductor substrate and the first diffusion layer across the junction of the first diffusion layer, the impurity concentration being larger than that of the semiconductor substrate, an insulator film produced to cover a portion of the second and third diffusion layers and the first diffusion layer, a pair of insulator films produced to cover a portion of the remaining area of the third diffusion layers, an electrode arranged to contact the second diffusion layer and to cover the insulator layer covering the first diffusion layer, and the electrode being connected the input terminal and the internal circuit proper of the semiconductor device, whereby the protection circuit allows positive surge voltages to escape, and becomes durable against negative surge voltages.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile