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:
Oct. 03, 2006
Filed:
Jan. 20, 2005
Roger E. Welser, Providence, RI (US);
Paul M. Deluca, Providence, RI (US);
Charles R. Lutz, Seekonk, MA (US);
Kevin S. Stevens, Providence, RI (US);
Noren Pan, Wilmette, IL (US);
Roger E. Welser, Providence, RI (US);
Paul M. Deluca, Providence, RI (US);
Charles R. Lutz, Seekonk, MA (US);
Kevin S. Stevens, Providence, RI (US);
Noren Pan, Wilmette, IL (US);
Kopin Corporation, Taunton, MA (US);
Abstract
A semiconductor material which has a high carbon dopant concentration includes gallium, indium, arsenic and nitrogen. The disclosed semiconductor materials have a low sheet resistivity because of the high carbon dopant concentrations obtained. The material can be the base layer of gallium arsenide-based heterojunction bipolar transistors and can be lattice-matched to gallium arsenide emitter and/or collector layers by controlling concentrations of indium and nitrogen in the base layer. The base layer can have a graded band gap that is formed by changing the flow rates during deposition of III and V additive elements employed to reduce band gap relative to different III–V elements that represent the bulk of the layer. The flow rates of the III and V additive elements maintain an essentially constant doping-mobility product value during deposition and can be regulated to obtain pre-selected base-emitter voltages at junctions within a resulting transistor.