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, 1994
Filed:
Apr. 09, 1992
Robert H Eklund, Plano, TX (US);
Ravishankar Sundaresan, Garland, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
This invention is an SOI BICMOS process which uses oxygen implanted wafers as the starting substrate. The bipolar transistor is constructed in two stacked epitaxial layers on the surface of the oxygen implanted substrate. A buried collector is formed in the first epitaxial layer that is also used for the CMOS transistors. The buried collector minimizes the collector resistance. Selective epitaxial silicon is then grown over the first epitaxial layer and is used to form the tanks for the bipolar transistors. An oxide layer is formed over the base to serve as an insulator between the emitter poly and the extrinsic base, and also as an etch stop for the emitter etch. The emitter is formed of a polysilicon layer which is deposited through an opening in the oxide layer such that the polysilicon layer contacts the epitaxial layer and overlaps the oxide layer.