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

Abstract

The conduction process as well as the unipolar resistive switching behavior of $\mathrm{Au}∕\mathrm{Hf}{\mathrm{O}}_2∕\mathrm{Ti}\mathrm{N}$ metal-insulator-metal structures were investigated for future nonvolatile memory applications. With current-voltage measurements performed at different temperatures $(200–400\mathrm{K})$ , the Poole–Frenkel effect as conduction process was identified. In particular, we extracted a trap energy level at ${\varphi }_t=0.35\pm 0.05\mathrm{eV}$ below the $\mathrm{Hf}{\mathrm{O}}_2$ conduction band to which a microscopic origin is tentatively assigned. From current-voltage measurements of $\mathrm{Au}∕\mathrm{Hf}{\mathrm{O}}_2∕\mathrm{Ti}\mathrm{N}$ structures, low-power (as low as $120\mu \mathrm{W}$ ) 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 $100\mu \mathrm{s}$ and a retention time upon continuous nondestructive readout of more than ${10}^4\mathrm{s}$ .