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:
Nov. 27, 2007
Filed:
Nov. 04, 2004
Keiichi Murayama, Okayama, JP;
Yorito Ota, Kobe, JP;
Akiyoshi Tamura, Suita, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
The present invention aims at providing a heterojunction bipolar transistor having improved breakdown voltage on operation for high power output, and includes: a GaAs semiconductor substrate; an n-type GaAs sub-collector layer; an n-type GaAs collector layer; a p-type GaAs base layer; an emitter layer; an n-type GaAs emitter cap layer; and an n-type InGaAs emitter contact layerThe emitter layerhas a multilayer structure including an n-type or non-doped first emitter layerand an n-type second emitter layerwhich are laminated in sequence. The first emitter layeris made of a semiconductor material including Al, while the second emitter layeris made of InGa1-xP (0<x<1).