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:
Feb. 08, 2005
Filed:
Apr. 11, 2002
Abdalla Aly Naem, Overijse, BE;
Abdalla Aly Naem, Overijse, BE;
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A bipolar transistor structure includes trench isolation dielectric material formed in a semiconductor substrate to define a substrate active device region. A collector region is formed beneath the surface of the active device region. A base region is formed in the active device region above the collector region and extends to the surface of the active device region. A layer of dielectric material is formed to extend at least partially over the trench isolation and over the surface of the base region. A layer of doped polysilicon is formed over the layer of dielectric material and extends over the edge of the layer of dielectric material and over the surface of the base region. The doped polysilicon is patterned to define a polysilicon emitter region that extends over the edge of the layer of dielectric material to provide an ultra-small emitter contact on the surface of the base region. Heating of the doped polysilicon causes dopant to diffuse into the polysilicon emitter contact through the surface of the base region beneath the polysilicon emitter contact. Dielectric sidewall spacers are formed on the sidewalls of the polysilicon emitter region to electrically isolate the polysilicon emitter sidewalls.