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:
Dec. 04, 2007
Filed:
Oct. 29, 2004
Applicant:
Takaki Niwa, Kanagawa, JP;
Inventor:
Takaki Niwa, Kanagawa, JP;
Assignee:
NEC Compound Semiconductor Devices, Ltd., Kawasaki-shi, Kanagawa, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L 29/739 (2006.01);
U.S. Cl.
CPC ...
Abstract
A heterojunction bipolar transistor, having a structure in which a subcollector layer of a first conductive type having a higher doping concentration than a collector layer, a collector layer of the first conductive type, a base layer of the second conductive type, and an emitter layer of the first conductive type are deposited, in order, on a semi-insulating semiconductor substrate, and in which a hole barrier layer of semiconductor material with a band gap wider than that of the base layer is inserted between the base layer and the collector layer, so as to be in direct contact with the base layer.