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. 02, 1999
Filed:
May. 21, 1997
Takehiro Hirai, Osaka, JP;
Mitsuo Tanaka, Osaka, JP;
Atsushi Hori, Osaka, JP;
Hiroshi Shimomura, Kyoto, JP;
Yoshihiko Horikawa, Osaka, JP;
Matsushita Electric Industrial Co. Ltd., Osaka, JP;
Abstract
In a semiconductor apparatus having a PNP bipolar transistor and high voltage resistance, there is formed an oxide insulating layer in the surface region of a P-type semiconductor substrate. In the above semiconductor substrate is formed a P-type collector layer so that at least a part of the P-type collector layer is in contact with said oxide insulating layer. In the surface region of said P-type collector layer is formed a P-type collector contact layer. An N-type base layer is formed in that region on the surface side of said P-type collector layer in which said P-type collector contact layer does not exist. A P-type emitter layer is formed on the surface side of said N-type base layer. A P-type collector-contact/base leakage prevention layer, which has a higher impurity concentration than said P-type collector layer, is formed at least in that region of said P-type collector layer which is in contact with said oxide insulating layer, so as to prevent the generation of a leakage current between said P-type collector contact layer and said N-type base layer.