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:
Nov. 06, 2007
Filed:
Feb. 22, 2006
Ryo Kanda, Gunma, JP;
Shuichi Kikuchi, Gunma, JP;
Seiji Otake, Saitama, JP;
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
In a conventional semiconductor device, there is a problem that an N-type diffusion region provided for protecting an element from an overvoltage is narrow and a breakdown current is concentrated so that a PN junction region for protection is broken. In a semiconductor device of the present invention, an N-type buried diffusion layer is formed across a substrate and an epitaxial layer. A P-type buried diffusion layer is formed across a wider region on an upper surface of the N-type buried diffusion layer so that a PN junction region for overvoltage protection is formed. A P-type diffusion layer is formed so as to be connected to the P-type diffusion layer. A breakdown voltage of the PN junction region is lower than a breakdown voltage between a source and a drain. With this structure, the concentration of the breakdown current is prevented so that the semiconductor device can be protected from the overvoltage.