04202044 is referenced by 66 patents and cites 1 patents.

A quaternary FET read only memory is disclosed wherein each FET storage element in the array has its threshold adjusted by ion-implantation to one of four values. Each FET element in the array has its drain connected to a drain potential V.sub.DD. A binary input signal from a conventional binary, true/complement generator will then enable the gate of a selected FET storage cell and the output potential at the source of that selected storage cell will be V.sub.DD minus the customized threshold voltage of that storage cell, which is output at an output node. The signal on the output node is a quaternary signal which may be amplified by a quaternary sense amplifier circuit and then converted from quaternary to binary signal by means of a converter. The quaternary read only memory is capable of storing twice as much information per unit area as is a conventional FET binary read only memory. The concept may be expanded to N levels of information storage, using FET array devices with N different threshold voltages.

Title
Quaternary FET read only memory
Application Number
5/915338
Publication Number
4202044
Application Date
June 13, 1978
Publication Date
May 6, 1980
Inventor
Harish N Kotecha
Manassas
VA, US
Kenneth E Beilstein Jr
Essex Junction
VT, US
Agent
John E Hoel
Assignee
International Business Machines Corporation
NY, US
IPC
G11C 11/40
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