Pulse-induced low-power resistive switching in HfO₂ metal-insulator-metal diodes for nonvolatile memory applications

The conduction process as well as the unipolar resistive switching behavior of Au/HfO₂/TiN metal-insulator-metal structures were investigated for future nonvolatile memory applications. With current-voltage measurements performed at different temperatures (200–400 K), the Poole–Frenkel effect as conduction process was identified. In particular, we extracted a trap energy level at Φ_t=0.35±0.05 eV below the HfO₂ conduction band to which a microscopic origin is tentatively assigned. From current-voltage measurements of Au/HfO₂/TiN structures, low-power (as low as 120 μW) resistive switching was observed. The required forming process is shown to be an energy-induced phenomenon. The characteristics include electric pulse-induced resistive switching by applying pulses up to 100 μs and a retention time upon continuous nondestructive readout of more than 10⁴ s.