Effects of W/Ir Top Electrode on Resistive Switching and Dopamine Sensing by Using Optimized TaO_x-Based Memory Platform

Resistive switching with best structural optimization by taking 100 devices of each structure including tungsten/iridium (W/Ir) top electrode effects and dopamine sensing by inserting 2 nm thick Al₂O₃ interfacial layer in TaO_x-based memory platform are reported for the first time. Statistical analysis of device-to-device switching uniformity for the formation voltage, low resistance state, and high resistance state is executed at low current compliance of 30 μA by inserting 2 nm thick Al₂O₃ layer underneath of W electrode in W/Al₂O₃/TaO_x/TiN structure. Incorporation of defective layer (TaO_x) into Ta₂O₅ layer is clearly observed from the high-resolution transmission electron microscope image of stressed device. A long program/erase endurance of >10⁸ cycles under low current of 30 μA with pulse width of 100 ns and retention of >900 h at 85 °C is obtained. Diode-like rectifying at 1 μA with higher ratio of >5000, nonlinearity factor of >300, and complementary resistive switching are achieved by using Ir electrode. Transport mechanism is dominated by Schottky conduction. Dopamine at a low concentration of 1 × 10⁻¹²m is detected through porous Ir in Ir/Al₂O₃/TaO_x/TiN structure owing to oxidation at the Ir/Al₂O₃ interface for the first time, which will be useful for early diagnosis of human diseases.