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:
Jul. 16, 2002
Filed:
Aug. 26, 1997
Applicant:
Inventors:
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 2/976 ; H01L 2/994 ;
U.S. Cl.
CPC ...
H01L 2/976 ; H01L 2/994 ;
Abstract
A semiconductor substrate is of a first conductivity type and has a retrograde well impurity concentration. A first of the first conductivity type and having a second impurity concentration with an impurity concentration peak is formed on a main surface of the semiconductor substrate. A first impurity layer of a third impurity concentration comes into contact with the underside of the retrograde well. The third impurity concentration is smaller than the impurity concentration peak of the first impurity concentration and the second impurity concentration. An element is formed on the retrograde well.