Browse Prior Art Database

Opposed Gate MOSFET

IP.com Disclosure Number: IPCOM000080467D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Grimes, DW: AUTHOR

Abstract

This device provides improved isolation between input and output circuits. Higher frequency operations; higher input impedance; less capacitance; less signal input current; less circuit leakage and an improved stability at higher frequency are among other advantages obtained by the device.

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Opposed Gate MOSFET

This device provides improved isolation between input and output circuits. Higher frequency operations; higher input impedance; less capacitance; less signal input current; less circuit leakage and an improved stability at higher frequency are among other advantages obtained by the device.

Gate terminals G(1) and G(2) are located on opposite surfaces of a semiconductor member. Both gate terminals G(1) and G(2) are isolated from the member by an oxide or like insulating film. Source and drain contacts are made to the N diffused regions. The voltage potential between G(1) and G(2) penetrates and influences the conductivity of the channel region between the source and drain diffusions. With a "+" to "-" potential on G(1) referenced to G(2), respectively, negative charges are induced in the P-channel between the source and drain diffusions. Positive charges are reduced in the P-channel between the source and drain. Thus the density of electrons in the P-channel is greatly enhanced and the density of the holes is depleted. The drain current will vary in a controlled manner, as the "+" to "-" potential between G(1) and G(2) is varied. The voltage between G(1) and G(2) controls the channel conductivity and hence the drain current and amplification is obtained.

The G(2) is not connected to the substrate. The lower capacitance between the substrate and G(2) is in series with the low capacitance between the drain and the substrate. Thus, a much lower total capacitance is present to the input signal, which allows higher frequency operation. A lower total capacitance has much less swamping effect over the output impedance of...