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:
Feb. 05, 1991
Filed:
Oct. 26, 1989
Applicant:
Inventors:
Kayoko Omoto, Hyogo, JP;
Kazuaki Miyata, Hyogo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ;
U.S. Cl.
CPC ...
357 23800 ; 357 23110 ; 357 23400 ;
Abstract
The semiconductor device is of high break down voltage type and has a source, drain and a gate deposited therebetween on the semiconductor substrate. The gate oxide film has a thick portion and below that portion, a doped layer as a drain is provided with two layers having different impurity concentration.