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:
Jul. 31, 2012
Filed:
Dec. 12, 2008
Keiji Mita, Gunma, JP;
Masao Takahashi, Saitama, JP;
Takao Arai, Gunma, JP;
Other;
Abstract
A conventional semiconductor device has a problem that, when a vertical PNP transistor as a power semiconductor element is used in a saturation region, a leakage current into a substrate is generated. In a semiconductor device of the present invention, two P type diffusion layers as a collector region are formed around an N type diffusion layer as a base region. One of the P type diffusion layers is formed to have a lower impurity concentration and a narrower diffusion width than the other P type diffusion layer. In this structure, when a vertical PNP transistor is turned on, a region where the former P type diffusion layer is formed mainly serves as a parasite current path. Thus, a parasitic transistor constituted of a substrate, an N type buried layer and a P type buried layer is prevented from turning on, and a leakage current into the substrate is prevented.