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. 26, 2009
Filed:
Nov. 09, 2007
Peter J. Geiss, Underhill, VT (US);
Alvin J. Joseph, Williston, VT (US);
Rajendran Krishnasamy, Essex Junction, VT (US);
Xuefeng Liu, South Burlington, VT (US);
Peter J. Geiss, Underhill, VT (US);
Alvin J. Joseph, Williston, VT (US);
Rajendran Krishnasamy, Essex Junction, VT (US);
Xuefeng Liu, South Burlington, VT (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A heterojunction bipolar transistor is formed in a semiconductor substrate of a first conductivity type including a collector region. A base region is formed on the substrate and an emitter region is formed over the base region. At least one of the collector, base and emitter regions includes a first region doped with an impurity having a first concentration and a second region doped with the impurity having a second concentration. Noise performance and reliability of the heterojunction bipolar transistor is improved without degrading ac performance.