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. 14, 2014
Filed:
Jul. 15, 2009
Shoyu Watanabe, Tokyo, JP;
Shuhei Nakata, Tokyo, JP;
Naruhisa Miura, Tokyo, JP;
Mitsubishi Electric Corporation, Tokyo, JP;
Abstract
In a power semiconductor device that switches at a high speed, a displacement current flows at a time of switching, so that a high voltage occurs which may cause breakdown of a thin insulating film such as a gate insulating film. A semiconductor device includes: a semiconductor substrate of a first conductivity type; a drift layer of the first conductivity type formed on a first main surface of the semiconductor substrate; a first well region of a second conductivity type formed in a part of a surface layer of the drift layer; a second well region of the second conductivity type formed in a part of the surface layer of the drift layer at a distance from the first well region, the second well region having a smaller area than that of the first well region when seen above an upper surface thereof; a low-resistance region of the first conductivity type formed in a surface layer of the first well region, the low-resistance region having a higher impurity concentration than that of the first well region; a gate insulating film formed on and in contact with a surface of the first well region; and a gate electrode formed on and in contact with a surface of the gate insulating film.