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. 07, 2006
Filed:
Dec. 03, 2004
Christopher J. Knorr, Los Gatos, CA (US);
Christopher J. Knorr, Los Gatos, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A bipolar junction transistor (BJT) structure and fabrication method are provided in which a doped polysilicon filled trench is utilized to form both the extrinsic base contact region and a vertical field plate. A sacrificial mandrel of dielectric material is formed over regions that will become the BJT active area. This allows the polysilicon filled trench to be extended above the original semiconductor substrate surface. In this way, the base-collector and emitter-base junctions are both self-aligned to the field plate trench. The field plate is utilized to control and shape the electric field in the base-collector depletion region, allowing heavier collector well doping for the same breakdown voltage. This results in improvement in both the breakdown/Rratio and the f*BVproduct.