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:
Aug. 06, 2019
Filed:
May. 18, 2017
Murata Manufacturing Co., Ltd., Kyoto-fu, JP;
Yasunari Umemoto, Nagaokakyo, JP;
Shigeki Koya, Nagaokakyo, JP;
Shigeru Yoshida, Nagaokakyo, JP;
Isao Obu, Nagaokakyo, JP;
MURATA MANUFACTURING CO., LTD., Kyoto-fu, JP;
Abstract
A heterojunction bipolar transistor includes a collector layer, a base layer, an emitter layer, and a semiconductor layer that are laminated in this order, wherein the emitter layer includes a first region having an upper surface on which the semiconductor layer is laminated, and a second region being adjacent to the first region and having an upper surface that is exposed, and the first and second regions of the emitter layer have higher doping concentrations in portions near the upper surfaces than in portions near an interface between the emitter layer and the base layer.