A nonlinear resistive switching behaviors of Ni/HfO2/TiN memory structures for self-rectifying resistive switching memory

Highlights: • The forming-free/self-rectifying resistive switching is achieved on crystalline HfO₂-based charge-trap type RRAM device. • Dependency of top electrode of crystalline HfO₂-based resistive switching memory device is investigated. • Ultra-low current level of • Ni TE shows the highest RM, which covers 56 × 56 arrays without any degradation. This work reports forming free/self-rectifying resistive switching characteristics and dependency of the top electrode (TE) of a crystalline HfO₂-based resistive switching memory device. In the memory cells, nonlinear bipolar resistive switching characteristics, i.e., an asymmetric current-voltage curve like the Schottky diode, was observed. In addition, the device exhibits resistive switching behaviors without forming process, which makes it possible to switch the resistance state under ultra-low current levels of V_SET was decreased when using TE with lower work function, and the height read margin was obtained in the sample with the Ni TE, covering over 56 × 56 arrays. Consequently, these results indicate that the interface control resistive switching properties in memory structures having the Schottky junction warrant the realization of selector-free resistive switching memory cells in a high-density crossbar array.