Memristor Resistance Modulation for Analog Applications

The resistance modulation (RM) of TaO
x
-based memristors can be precisely controlled by the SET switching compliance current. After electroforming, switching occurs in a rebuilt oxide between the electroformed conductive filament and the Pt electrode. RM is independent of initial oxide thickness. The switching mechanism is postulated as dielectric breakdown at the sidewall of the conductive channel created within the rebuilt oxide: During a SET operation to a lower resistance state, the conductive channel increases in size, conducting a larger current until limited by the external compliance; during a RESET operation to a higher resistance state, the tip of the oxygen-saturated tantalum conductive channel is oxidized, reforming the rebuilt oxide. The conduction of the rebuilt oxide follows a power law function of voltage, in parallel with the modulated channel conductance. The linear resistance can be randomly programmed with accuracy and reproducibility. Analog circuits of tunable memristive low-pass and high-pass filters demonstrate frequency tuning by RM.