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:
Sep. 28, 1999
Filed:
Jul. 29, 1998
Applicant:
Inventor:
Takashi Nakashima, Hyogo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ; H01L / ; H01L / ;
U.S. Cl.
CPC ...
438207 ; 438218 ; 438234 ; 438564 ;
Abstract
An improved bipolar transistor of BiCMOS is provided to improve the breakdown voltage between a collector and a base. A low concentration diffusion layer is provided at a main surface of a semiconductor substrate at a boundary between an outer perimeter of an external base layer and an end portion of a field oxide film. The low concentration diffusion layer expands from the main surface of the semiconductor substrate toward the inside of the substrate and has a concentration lower than the impurity concentration of the external base layer.