US Patent 9118007 RRAM with dual mode operation

A two-terminal memory cell comprises a dual mode of operation in a unipolar mode and bipolar mode for a programming or On-state and for an erase or Off-state of the cell. The two-terminal memory cell is field programmable and can be flexibly designed or integrated into existing architecture. The two-terminal memory comprises a first electrode layer and a second electrode layer with a switching layer disposed between that has an electrical insulator material. A semiconductor layer is disposed between the switching layer and at least one of the first electrode or the second electrode. The switching layer generates a conductive path that is configured to be in a program state and an erase state, based on a bipolar mode and a unipolar mode.