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. 15, 1992
Filed:
Feb. 18, 1992
Shin-ichi Taka, Yokosuka, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A bipolar transistor includes a p-type external base region formed on the major surface of an n-type semiconductor substrate, a plurality of p-type internal base regions formed to be surrounded by the external base region, and emitter regions of a first conductivity type respectively formed in the internal base regions. An oxide film and a nitride film, stacked on each other, extend outward from an outer peripheral portion of the external base region on the major surface of the semiconductor substrate, and define openings therein. A p-type semiconductor film is formed on the external base region in the openings. A first conductive layer having a p-type semiconductor is formed on the nitride film and the semiconductor film. Side-wall-like oxide films are formed on side wall portions, of the semiconductor film and the first conductive layer, opposite to the emitter regions. A second conductive layer having an n-type semiconductor and serving as an emitter electrode extraction portion is formed on the side-wall-like oxide films to be in contact with the emitter regions.