Bipolar Nonlinear $\hbox{Ni/TiO}_{2}\hbox{/}\hbox{Ni}$ Selector for 1S1R Crossbar Array Applications

A bipolar nonlinear selector to suppress the sneak current in the crossbar array has been fabricated using a simple Ni/TiO ₂ /Ni metal-insulator-metal structure. The highly nonlinear current-voltage characteristics are realized by the Schottky emission over the Ni/TiO ₂ barriers. The series connection with an HfO ₂ -resistive memory device shows reproducible bipolar resistive switching. The maximum array size with at least 10% read margin is projected to exceed megabits. This letter demonstrates the promise of the compact one selector-one resistor (1S1R) cell structure for high-density crossbar array applications.