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:
Nov. 23, 2010
Filed:
May. 25, 2007
Mingwei Xu, South Portland, ME (US);
Jamal Ramdani, Scarborough, ME (US);
Mingwei Xu, South Portland, ME (US);
Jamal Ramdani, Scarborough, ME (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A system and method are disclosed for providing an improved polyemit module for a self aligned heterojunction bipolar transistor architecture. The polyemit module of the transistor of the present invention is formed using a double layer deposition process. In the double layer deposition process, the first layer is a layer of emitter polysilicon and the second layer is a sacrificial layer of silicon germanium (SiGe). The shape and thickness of the emitter polysilicon layer of the polyemit module provides (1) a reduction in the overall resistance of the emitter and (2) an increase in the contact area between the emitter polysilicon layer and a contact structure that is more than three times the contact area that is provided in prior art polyemit modules.