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:
Mar. 15, 2005
Filed:
Aug. 08, 2002
Reinhard Stengl, Stadtbergen, DE;
Thomas Meister, Taufkirchen, DE;
Herbert Schäfer, Höhenkirchen-Siegertsbrunn, DE;
Martin Franosch, München, DE;
Reinhard Stengl, Stadtbergen, DE;
Thomas Meister, Taufkirchen, DE;
Herbert Schäfer, Höhenkirchen-Siegertsbrunn, DE;
Martin Franosch, München, DE;
Infineon Technologies AG, Munich, DE;
Abstract
A bipolar transistor includes a first layer with a collector. A second layer has a base cutout for a base. A third layer includes a lead for the base. The third layer is formed with an emitter cutout for an emitter. An undercut is formed in the second layer adjoining the base cutout. The base is at least partially located in the undercut. In order to obtain a low transition resistance between the lead and the base, an intermediate layer is provided between the first and the second layer. The intermediate layer is selectively etchable with respect to the second layer. At least in the region of the undercut between the lead and the base, a base connection zone is provided that can be adjusted independent of other production conditions. The intermediate layer is removed in a contact region with the base.