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:
Jan. 07, 2014
Filed:
Jun. 18, 2012
Koji Shirai, Kanagawa, JP;
Koji Shirai, Kanagawa, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A semiconductor device includes an n-type first guard ring layer provided between an emitter layer and a collector layer on a surface side of a base layer, and having a higher n-type impurity concentration than the base layer, and an n-type second guard ring layer provided between the first guard ring layer and a buried layer, connected to the first guard ring layer and the buried layer, and having a higher n-type impurity concentration than the base layer. The first guard ring layer has an n-type impurity concentration profile decreasing toward the second guard ring layer side, and the second guard ring layer has an impurity concentration profile decreasing toward the first guard ring layer side.