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:
Aug. 17, 1999
Filed:
Oct. 16, 1996
Frank J Morris, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A method for fabricating a bipolar transistor comprising the steps of: implanting portions 320 of a semiconductor material structure with ions to render the portions semi-insulating; forming an emitter contact region 332 at an exposed surface of a base layer 308 in a non-implanted portion of the material structure; forming an epitaxial layer of semiconductor material 322 over the exposed surface in an implanted portion of the material structure; and forming a base contact 330 over said epitaxial layer. In accordance with one embodiment of the invention, the method includes the further step of forming a second epitaxial layer of semiconductor material 324 over the first epitaxial layer 322 and then forming the base contact 330 on the second epitaxial layer 324. In accordance with another embodiment, the method includes the further step of forming a second layer of epitaxial material over the exposed surface prior to forming the epitaxial layer of semiconductor material. The base layer may be GaAs and the epitaxial of semiconductor material may be AlGaAs. The second epitaxial layer may also be GaAs.