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:
Sep. 13, 2005
Filed:
Apr. 09, 2003
Isao Ohbu, Sagamihara, JP;
Tomonori Tanoue, Machida, JP;
Chushiro Kusano, Niza, JP;
Yasunari Umemoto, Sayama, JP;
Atsushi Kurokawa, Takasaki, JP;
Kazuhiro Mochizuki, Tokyo, JP;
Masami Ohnishi, Hachioji, JP;
Hidetoshi Matsumoto, Kokubunji, JP;
Isao Ohbu, Sagamihara, JP;
Tomonori Tanoue, Machida, JP;
Chushiro Kusano, Niza, JP;
Yasunari Umemoto, Sayama, JP;
Atsushi Kurokawa, Takasaki, JP;
Kazuhiro Mochizuki, Tokyo, JP;
Masami Ohnishi, Hachioji, JP;
Hidetoshi Matsumoto, Kokubunji, JP;
Renesas Technology Corp., Tokyo, JP;
Abstract
In a semiconductor device using an emitter top heterojunction bipolar transistor having a planar shape in a ring-like shape, a structure is provided in which a base electrode is present only on an inner side of a ring-like emitter-base junction region. This allows reduction of base/collector junction capacitance per unit emitter area, whereby a semiconductor device having high power adding efficiency and high power gain suitable for a power amplifier can be realized. Further, in a multistage power amplifier including first and second amplifier circuits each having one or more of bipolar transistors, a bipolar transistor in the first amplifier circuit uses an emitter having a planar shape in a rectangular shape, and a bipolar transistor in the second amplifier circuit uses an emitter having a ring-like shape and a base electrode only on the inner side of the emitter.