Charge-stabilized memory

Abstract

A dense memory is provided which includes a one device random access memory cell using charge fill and spill techniques wherein a potential well under a storage node is filled with charge and the excess charge above a predetermined level is spilled to a diffusion or drain region connected to a sense line through a channel region controlled by pulses on a word line. One bit or two or more bits of information may be stored in the potential well at any given instant of time. Depending upon the value of the increment of voltage applied to the storage node or electrode, a given analog charge packet is stored in a potential well formed under the storage electrode. Information is read by applying a voltage to the word line to turn on the channel region and then stepping down the voltage on the storage electrode in fractional, preferably one half, increments. Charge from a charge packet spilled from the potential well under the storage electrode is detected by a sensing circuit connected to the sense line. To rewrite information into the potential well, the original increment of voltage is applied to the storage node and the sense line is pulled to ground so that the diffusion region acts as a source of charge for the potential well.