Nonvolatile Static Random Access Memory Using Resistive Switching Devices: Variable-Transconductance Metal--Oxide--Semiconductor Field-Effect-Transistor Approach

In this paper, we present a variable-transconductance ($g_{\text{m}}$) metal--oxide--semiconductor field-effect-transistor (VGm-MOSFET) architecture using a nonpolar resistive switching device (RSD) for nonvolatile bistable circuit applications. The architecture can be achieved by connecting an RSD to the source terminal of an ordinary MOSFET. The current drive capability of the VGm-MOSFET can be modified by resistance states of the connected RSD, which is a very useful function for nonvolatile bistable circuits, such as nonvolatile static random access memory (NV-SRAM) and nonvolatile flip-flop (NV-FF). NV-SRAM can be easily configured by connecting two additional VGm-MOSFETs to the storage nodes of a standard SRAM cell. Using our developed SPICE macromodel for nonpolar RSDs, successful circuit operations of the proposed NV-SRAM cell were confirmed.