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:
Apr. 16, 1991
Filed:
Sep. 11, 1989
Jeffrey L Blouse, Stanfordville, NY (US);
Inge G Fulton, Washingtonville, NY (US);
Russell C Lange, Newburgh, NY (US);
Bernard S Meyerson, Yorktown Heights, NY (US);
Karen A Nummy, Newburgh, NY (US);
Martin Revitz, Poughkeepsie, NY (US);
Robert Rosenberg, Peekskill, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
There is provided a method for use in the fabrication of a transistor, the method including the steps of: providing a substrate of semiconductor material including a region of first conductivity type; forming a first layer of second conductivity type epitaxial semiconductor material over the region; forming a second layer of second conductivity type epitaxial semiconductor material over the first layer, the second layer of a relatively higher dopant concentration than the first layer; oxidizing a portion of the second layer; and removing the oxidized portion of the second layer to expose a portion of the first layer, the exposed portion of the first layer forming an intrinsic base region. The steps of forming the first and second layers are preferably performed using low temperature, ultra-high vacuum, epitaxial deposition processes.