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:
Jul. 28, 2009
Filed:
Oct. 20, 2004
Eric M. Rehder, Providence, RI (US);
Roger E. Welser, Providence, RI (US);
Charles R. Lutz, Seekonk, MA (US);
Eric M. Rehder, Providence, RI (US);
Roger E. Welser, Providence, RI (US);
Charles R. Lutz, Seekonk, MA (US);
Kopin Corporation, Taunton, MA (US);
Abstract
A bipolar transistor includes a base layer design and a method for fabricating such a bipolar transistor that employ a built-in accelerating field focused on a base region adjacent to a collector, where minority carrier transport is otherwise retarded. The accelerating field of the base layer includes on average, a relatively low p-doping level in a first region proximate to the collector and a relatively high p-doping level in a second region proximate to an emitter. Alternatively, the accelerating field can be derived from band gap grading, wherein the grade of band gap in the first region is greater than the grade of band gap in the second region, and the average band gap of the first region is lower than that of the second region.