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:
Jan. 23, 1990
Filed:
Aug. 23, 1988
Yasutomo Kajikawa, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In the inventive heterojunction bipolar transistor and method of manufacturing the same, a semi-insulation layer and an external base layer sequentially epitaxially grown on a collector layer are selectively mesa-etched through a mask of an insulation film provided with an opening so that the external base layer, the semi-insulation layer and the collector layer are selectively exposed, and thereafter an internal base layer and an emitter layer are selectively epitaxially grown in sequence on the exposed regions of an external base layer, the semi-insulation layer and the collector layer. An emitter electrode is formed in a self-alignment manner through the opening of the insulation film. Thus, transistor performance is improved and a precision element size is able to be obtained.