Ultra-low voltage resistive switching of HfO2 buffered (001) epitaxial NiO films deposited on metal seed layers

Abstract

A set of (001) epitaxial NiO films were prepared on highly textured (001) Pt seed layers using magnetron sputtering, and their resistive switching performance was measured. Cube-to-cube epitaxial relationships of NiO(001)//Pt(001) and NiO[001]//Pt[001] were demonstrated. Current-voltage measurements revealed that the Ag/(001)NiO/(001)Pt capacitor structures exhibited stable bipolar switching behavior with an ON/OFF ratio of 20 and an endurance of over 5 × 103 cycles. Furthermore, inserting a HfO2 buffer layer between the NiO film and the Ag top electrode increased the ON/OFF ratio to more than 103 and reduced the SET/RESET voltage to below ±0.2 V. These enhancements are attributed to the differing filament growth mechanisms that occur in the NiO and HfO2 layers. The present work suggests that Ag/HfO2/(001)NiO/(001)Pt capacitor structures are a promising technology for next-generation, ultra-low voltage resistive switching memory.