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:
Sep. 14, 2004
Filed:
May. 30, 2003
Wen-Chau Liu, Tainan, TW;
Shiou-Ying Cheng, Taipei Hsien, TW;
National Cheng Kung University, Tainan, TW;
Abstract
A bipolar heterojunction transistor (HBT) includes a collector layer, a base layer formed on the collector layer, a first transition layer formed on the base layer, an emitter layer formed on the first transition layer, a second transition layer formed on the emitter layer, and an emitter cap layer formed on the second transition layer. Each of the first and second transition layers is formed of a composition that contains an element, the mole fraction of which is graded in such a manner that the conduction band of the HBT is continuous through the base layer, the first and second transition layers, the emitter layer and the emitter cap layer.