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:
Apr. 18, 1995
Filed:
Sep. 28, 1992
Applicant:
Inventor:
Akio Uenishi, Itami, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ;
U.S. Cl.
CPC ...
257339 ; 257345 ; 257378 ; 257341 ;
Abstract
A semiconductor device comprises a first conductivity type semiconductor layer and a second conductivity type well region which is formed on the semiconductor layer. The well region includes a first semiconductor region of a first depth and a second semiconductor region of a second depth deeper than the first depth which is provided in the central portion of the first semiconductor region. The ratio of the first depth to the second depth is settled in a range from 0.85 to 0.95 in order to increase the breakdown voltage of the semiconductor device.