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:
May. 02, 2006
Filed:
Dec. 18, 2003
Masaki Yanagisawa, Yokohama, JP;
Masaki Yanagisawa, Yokohama, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
This invention provides a double hetero-junction bipolar transistor (DHBT) in which a probability of the impact ionization at the interface between the base and the collector is reduced, thereby enhancing the break down voltage. In the present DHBT, a plurality of transition layers is inserted between the base layer and the collector layer. Each transition layers has an energy band gap gradually increasing from the base to the collector, and comprises a doped layer close to the base and an un-doped layer. Transition layers thus configured may bring both characteristics of the high break down voltage by the reduction of the average doping concentration and the capability of the high-speed operation by the reduction of the junction capacitance.