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. 20, 1999
Filed:
Feb. 20, 1997
Christopher S Blair, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A merged single polysilicon bipolar NPN transistor, rather than using separate isolation islands for emitter-base and collector contacts, utilizes a single isolation island. This significantly reduces device area because elimination of the second isolation island used in conventional designs reduces the N+ sink to NPN spacing. Buried layer and isolation layer processing proceed in the conventional manner. At sink mask, however, the mask is sized to uncover one end of the main device active region and a sink implant is performed. At base mask, the sink implant remains covered, rather than being exposed as in the conventional flow. At silicide exclusion, the oxide spacer layer is patterned to exclude silicide from the area above the sink implant region.