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. 11, 1989
Filed:
Oct. 30, 1987
David J Frank, Tarrytown, NY (US);
Ronald F Marks, Ossining, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Heterojunction bipolar transistors are disclosed having an energy band offset in the valence or conduction band and the other of the bands being substantially aligned at the heterojunction. For an npn transistor the conduction band is substantially aligned and the bandgap difference is in the valence band. A pnp type transistor is also disclosed wherein all the bandgap difference is in the conduction band and the valence band is substantially aligned. The npn type transistor provides improved hole confinement in the base as well as enhanced electron injection and collection. In one embodiment of a double heterojunction bipolar transistor, materials are selected that utilize Ga compounds in the base and Al and/or In compounds in the emitter and collector, which have a valence band offset of approximately 400 meV or greater and an aligned conduction band at both of the heterojunctions.