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:
Jan. 24, 2006
Filed:
Dec. 23, 2002
Timothy Jonathan Phillips, Malvern, GB;
Timothy Jonathan Phillips, Malvern, GB;
Qinetiq Limited, , GB;
Abstract
A bipolar transistor with vertical geometry comprises a base region () provided with a base contact (), emitter and collector regions () arranged to extract minority carriers from the base region, and an excluding structure for counteracting entry of minority carriers into the base region via the base contact, wherein the base region has a bandgap of greater than 0.5 eV and a doping level greater than 10cm. As shown the base includes an excluding heterojunction () preventing entry of carriers from the base contact (), but alternatively the base region could comprise a 'high-low' doping homojunction. The construction shows improved resistance to thermal runaway even in multi-finger transistors. It is particularly useful for high power, high frequency transistors, e.g. base on gallium indium arsenide. The collector region preferably has a heterostructure.