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:
Jul. 07, 2015
Filed:
Feb. 12, 2010
Mutsuo Ogura, Tsukuba, JP;
Sungwoo Choi, Tsukuba, JP;
Nobuyuki Hayama, Tsukuba, JP;
Katsuhiko Nishida, Tsukuba, JP;
Mutsuo Ogura, Tsukuba, JP;
SungWoo Choi, Tsukuba, JP;
Nobuyuki Hayama, Tsukuba, JP;
Katsuhiko Nishida, Tsukuba, JP;
Abstract
A hetero-junction bipolar phototransistor includes a photo-absorption layer formed of a first conductivity type semiconductor layer, and a collector operating as a barrier layer, a base layer, and an emitter layer, which are stacked in sequence on the photo-absorption layer. The photo-absorption layer, collector, base layer and emitter layer forms a first mesa structure, and an emitter contact layer forms a second mesa structure. The photo-absorption layer includes a semiconductor layer with a narrow gap corresponding to a light-sensing wavelength of the phototransistor. The collector includes a semiconductor layer with a wider gap than a gap of the photo-absorption layer. The base layer has an energy level equal to or higher than the energy level of the collector. The emitter layer has a wide gap as compared to the base layer, and an energy level in a valence band is lower than an energy level of the base layer.