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:
Nov. 30, 2010
Filed:
Jul. 13, 2006
Makoto Miura, Hachioji, JP;
Katsuyoshi Washio, Tokorozawa, JP;
Hiromi Shimamoto, Iruma, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A semiconductor device capable of avoiding generation of a barrier in a conduction band while maintaining high withstanding voltage and enabling high speed transistor operation at high current in a double hetero bipolar transistor, as well as a manufacturing method thereof, wherein a portion of the base and the collector is formed of a material with a forbidden band width narrower than that of a semiconductor substrate, a region where the forbidden band increases stepwise and continuously from the emitter side to the collector side is disposed in the inside of the base and the forbidden band width at the base-collector interface is designed so as to be larger than the minimum forbidden band width in the base, whereby the forbidden band width at the base layer edge on the collector side can be made closer to the forbidden band width of the semiconductor substrate than usual while sufficiently maintaining the hetero effect near the emitter-base thereby capable of decreasing the height of the energy barrier generated upon increase of the collector current and enabling satisfactory transistor operation at high current.