Method of fabricating bipolar transistors with independent impurity profile on the same chip

US6472288B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Gregory G. Freeman · Hopewell Junction, US
• K. T. Schonenberg · New Fairfield, US
• Kenneth J. Stein · Sandy Hook, US
• Seshadri Subbanna · Brewster, US

Key dates

• Filing date: Dec 8, 2000
• Grant date: Oct 29, 2002
• Expiry date: Dec 8, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/933

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.