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. 05, 2010
Filed:
May. 18, 2007
Mingwei Xu, South Portland, ME (US);
Steven J. Adler, Cape Elizabeth, ME (US);
Mingwei Xu, South Portland, ME (US);
Steven J. Adler, Cape Elizabeth, ME (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A system and method are disclosed for providing a self aligned bipolar transistor using a sacrificial polysilicon external base. An active region of a transistor is formed and a sacrificial polysilicon external base is formed above the active region of the transistor and covered with a silicon oxide layer. Then an emitter window is etched and filled with silicon nitride. An etch procedure is subsequently performed to remove the sacrificial polysilicon external base. A layer of doped polysilicon material is then deposited to fill a cavity within the transistor formed by the removal of the sacrificial polysilicon external base. A polysilicon emitter structure is subsequently formed in the emitter window. The self aligned bipolar transistor architecture of the invention is compatible with BiCMOS technology.