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:
Oct. 29, 2002
Filed:
Dec. 08, 2000
Gregory G. Freeman, Hopewell Junction, NY (US);
K. T. Schonenberg, New Fairfield, CT (US);
Kenneth J. Stein, Sandy Hook, CT (US);
Seshadri Subbanna, Brewster, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Bipolar transistors of different designs, particularly designs optimized for different high frequency applications are formed on the same substrate by separate base layer formation processes for epitaxial growth including different material concentration profiles of germanium, boron and/or carbon. Epitaxial growth of individual growth layers by low temperature processes is facilitated by avoiding etching of the silicon substrate including respective collector regions through use of an etch stop that can be etched selectively to silicon. Annealing processes can be performed between growth of respective base layers and/or performed collectively after all transistors are substantially completed.