PROCESS OF READING A SELECTED CELL IN A CAPACITOR MEMORY ARRAY

摘要

An improved method for reading metal dual insulator semiconductor capacitor memories is disclosed. The memory contains a plurality of capacitor cells, each cell comprising a semiconductor substrate layer and a high conductivity layer sandwiching two insulator layers. The substrate is doped to provide avalanche breakdown in a surface depletion layer at a voltage comparable to the write voltage in the accumulation direction. According to the invention, a small variable voltage is applied across a selected cell or cells. The range of voltage includes a "flat-band" portion of the hysteresis loop describing the voltage-capacitance relationship for the capacitor memory. The unselected cells are maintained in a depletion state in which their capacitance is a minimum. A change or the absence of a change in the current through the capacitor indicates the state of the capacitor cell.