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:
May. 28, 1991
Filed:
Aug. 30, 1989
Applicant:
Inventors:
Katsuhiko Mitani, Kokubunji, JP;
Tomonori Tanoue, Ebina, JP;
Chushiro Kusano, Tokorozawa, JP;
Masayoshi Kobayashi, Hachioji, JP;
Susumu Takahashi, Tokyo, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ;
U.S. Cl.
CPC ...
437 31 ; 437126 ; 437133 ; 437909 ; 148D / ; 148D / ; 148D / ;
Abstract
Disclosed is a semiconductor device including a heterojunction bipolar transistor in which the front surface of a base layer and the surface of an emitter-base junction are covered with a high-resistivity layer of compound semiconductor containing at least one constituent element common to an emitter layer and the base layer.