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:
Apr. 19, 2005
Filed:
Aug. 14, 2002
Takaki Niwa, Kawasaki, JP;
Hidenori Shimawaki, Kawasaki, JP;
Koji Azuma, Kawasaki, JP;
Naoto Kurosawa, Kawasaki, JP;
Takaki Niwa, Kawasaki, JP;
Hidenori Shimawaki, Kawasaki, JP;
Koji Azuma, Kawasaki, JP;
Naoto Kurosawa, Kawasaki, JP;
Abstract
A heterojunction bipolar transistor has a raised breakdown voltage and restrains the rising characteristic of I-Vcharacteristic from degrading. The collector region includes first, second, and third collector layers of semiconductor. The first collector layer is made of a doped or undoped semiconductor in such a way as to contact the sub-collector region. The second collector layer is made of a doped or undoped semiconductor having a narrower band gap than the first collector layer in such a way as to contact the base region. The third collector layer has a higher doping concentration than the second collector layer in such a way as to be located between or sandwiched by the first collector layer and the second collector layer.