Browse Prior Art Database

Differential Field Effect Transistor

IP.com Disclosure Number: IPCOM000084413D
Original Publication Date: 1975-Nov-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Cade, PE: AUTHOR

Abstract

Junction field-effect transistors (FET's) can be created in a bipolar-type configuration by providing vertical channels through the normal bipolar base region. Such junction field-effect transistors have the speed of bipolar transistors and the density of metal-oxide semiconductor field-effect transistors.

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Differential Field Effect Transistor

Junction field-effect transistors (FET's) can be created in a bipolar-type configuration by providing vertical channels through the normal bipolar base region. Such junction field-effect transistors have the speed of bipolar transistors and the density of metal-oxide semiconductor field-effect transistors.

Such devices are created by providing, as shown in Fig. 1a, in a semiconductor body 10, a low-resistivity subcollector 11 of the opposite doping polarity by diffusion or ion implantation. A high-resistivity epitaxial layer 12 is then formed on the semiconductor. This region is also the same doping polarity as the subcollector 11. Epitaxial pockets are then formed in the usual fashion by isolating diffusions or implants 13, of the same doping polarity as the semiconductor body 10.

Once the pocket has been formed, a base region 14 is defined in the epitaxy 12 with vertical cylindrical channels 15 and 16 thus formed of epitaxial material. Emitter diffusions 18 and 19 of the same type doping polarity as the subcollector 11 are placed over the channels 15 and 16 created through the base regions 14 to provide suitable ohmic contacts when required. Interconnecting metallurgy may also contact the channel but the contact formed is essentially nonohmic and forms a Schottky diode. An additional emitter diffusion 17 is formed simultaneously to provide ohmic contact to the subcollector 11 thru the epitaxy
12.

If two channels are provided...