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:
Jan. 16, 2007
Filed:
Jul. 28, 2005
Lily Springer, Dallas, TX (US);
Lily Springer, Dallas, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A method of forming a bipolar transistor device, and more particularly a vertical poly-emitter PNP transistor, as part of a BiCMOS type manufacturing process is disclosed. The formation of the PNP transistor during a CMOS/DMOS fabrication process requires merely one additional mask to facilitate formation of a very small emitter in a portion of an N-type surface layer of a double diffused well (DWELL). Unlike conventional PNP transistors, a separate mask is not required to establish the base of the transistor as the transistor base is formed from a portion of the double diffused well and the DWELL includes a P-type body layer formed via implantation through the same opening in the same mask utilized to establish the N-type surface layer of the double diffused well. The base is also thin thus improving the transistor's frequency and gain.