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. 25, 1989
Filed:
Apr. 04, 1988
Shigeru Komatsu, Kitakyushu, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An n.sup.+ -type buried layer is formed in the surface region of a p-type semiconductor substrate. Isulating films are formed on the semiconductor substrate. The insulating films have openings located above the buried layer. An n-type monocrystalline silicon layer is formed in one opening located above the buried layer. A base region is formed in the monocrystalline silicon layer. The base region defines a remaining portion of the monocrystalline silicon layer as a collector region. An emitter region is formed in the base region. A polycrystalline silicon layer is buried in the insulating films to have ohmic contact with the base region and serve as a portion of a base connection region. The polycrystalline silicon layer contains a p-type impurity and serves as an impurity diffusion source for the formation of an external base of the base region. An MoSi.sub.2 layer is buried in the insulating films to have ohmic contact with the polycrystalline silicon layer and to serve as a portion of the base connection region, thereby reducing the base resistance. A conductive layer for connection with a collector is formed in another opening.