Nonvolatile SRAM cell using different capacitance loading

Abstract

A simple and novel nonvolatile SRAM (NVSRAM) cell is proposed. NVSRAM cell can be achieved by adding only one nonvolatile device with split floating gates to a conventional SRAM cell. It acts as a conventional SRAM cell under normal operation. SRAM cell data are programmed to the nonvolatile device by hot electron injection. At power up, data are restored using different capacitance loading resulting from the split floating gate. The operations have been confirmed by circuit simulation. The NVSRAM cell is symmetric, and therefore has better retention characteristics than other NVSRAM cells.