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:
Dec. 08, 2009
Filed:
Jul. 28, 2009
Eisuke Suekawa, Tokyo, JP;
Eisuke Suekawa, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
One of the aspects of the present invention is to provide a semiconductor device, which includes a semiconductor layer of a first conductive type having first and second surfaces. The semiconductor layer includes a base region of a second conductive type formed in the first surface and an emitter region of the first conductive type formed in the base region. Also, the semiconductor device includes a buffer layer of the first conductive type formed on the second surface of the semiconductor layer, and a collector layer of the second conductive type formed on the buffer layer. The buffer layer has a maximal concentration of the first conductive type impurity therein of approximately 5×10cmor less, and the collector layer has a maximal concentration of the second conductive type impurity therein of approximately 1×10cmor more. Further, the ratio of the maximal concentration of the collector layer to the maximal concentration of the buffer layer being greater than 100. The collector layer has a thickness of approximately 1 μm or less.