Novel Defects-Trapping ${\rm TaO}_{\rm X}/{\rm HfO}_{\rm X}$ RRAM With Reliable Self-Compliance, High Nonlinearity, and Ultra-Low Current

The dependence of resistive switching of Ta/TaO_X/HfO_X device governed by general filamentary or novel defects-trapping mechanism on the operation current is demonstrated in this letter. The device with stable resistive switching, high nonlinearity, and robust self-compliance ~ 1 μA is demonstrated, which can be integrated in the vertical RRAM structure. Based on constant current density switching ( ~ 10³ A/cm²) governed by defects-trapping transport, where the low and high resistance states attributed to the resistance of Ta/TaO_X layer and device initial state, the switching current reduction by scaling down the cell size is proposed in transition metal oxide RRAM.