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High Frequency Field Effect Transistor

IP.com Disclosure Number: IPCOM000075589D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Laibowitz, RB: AUTHOR [+2]

Abstract

A field-effect transistor is provided with a narrow-gate region in the semiconductor channel between source and drain. The channel is induced in the semiconductor by a wider gate insulated from the narrow-gate electrode. Production of field-effect transistors are provided having superior switching, frequency and reliability characteristics than prior devices.

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High Frequency Field Effect Transistor

A field-effect transistor is provided with a narrow-gate region in the semiconductor channel between source and drain. The channel is induced in the semiconductor by a wider gate insulated from the narrow-gate electrode. Production of field-effect transistors are provided having superior switching, frequency and reliability characteristics than prior devices.

The switching speed and frequency response of present field-effect transistors is limited by the relatively long-channel length that is used in these devices. Typically, 1 micron is the limiting length and frequency response above 10 GHz is limited. This device has a very short-channel length. The structure shown in the Figure uses two gates where one is an ultrathin stripe of the type made using electron beam technique. Any convenient metal may be used for the gates, e.g. Al, and a wide choice is available for the semiconductor. Si is used in the example.

In the two-gate field-effect transistor, oxides 1 and 2 may be the same or different material and oxide 1 may be made thicker than oxide 2, e.g., oxide 2 may be 200 Angstroms, oxide 1 may be 2000 Angstroms thick. In operation of the device, a potential is applied to gate 1 to establish the channel region between the source and drain. Once the channel is established, signals may be applied to gate 2. By making gate 2 very narrow, e.g. 0.05 microns as shown in the Figure, a new active channel is created which is much shorter than the orig...