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:
Dec. 06, 2005
Filed:
Mar. 24, 2003
Quasi self-aligned single polysilicon bipolar active device with intentional emitter window undercut
Steven M. Leibiger, Falmouth, ME (US);
Daniel J. Hahn, Portland, ME (US);
Laurence M. Szendrei, Gray, ME (US);
Steven M. Leibiger, Falmouth, ME (US);
Daniel J. Hahn, Portland, ME (US);
Laurence M. Szendrei, Gray, ME (US);
Fairchild Semiconductor Corporation, Portland, ME (US);
Abstract
An emitter stack for a quasi-self-aligned bipolar (NPN or PNP) transistor is formed where two layers over the emitter of a silicon substrate are windowed in a manner to under cut the top layer thereby exposing the substrate material. The emitter polysilicon structure is then formed over the window and conformally extends into the undercut region thereby widening the emitter region and so reducing the distance between the edge of the emitter and the extrinsic base (the base link distance) and therefore reducing the total base resistance of the transistor.