Ultralow Set Voltage and Enhanced Switching Reliability for Resistive Random-Access Memory Enabled by an Electrodeposited Nanocone Array.

Resistive random-access memory (RRAM) has been extensively investigated for 20 years due to its excellent advantages, including scalability, switching speed, compatibility with the complementary metal oxide semiconductor process, and neuromorphic computing application. However, the issue of memristor reliability for cycle to cycle and device to device resulting from the random ion drift and diffusion in solid-state thin films is still a great challenge for commercialization. Therefore, controlling the internal ionic process to improve the memristor performance and reliability is a primary and urgent task. Here, a Ni nanocone array prepared by an electrodeposition method is integrated with an Ag/Al2O3/Pt resistive switching device. The nanocone-array-based memristor yields superior switching performance, including an ultralow set voltage (-0.37 V), a concentrated voltage/resistance distribution (CV 14.8%/32.7%), robust endurance (>105 cycles), and multilevel storage capability. A finite element analysis, transmission electron microscope observation, and current mapping test indicate that the local enhancement of the electric field confines the ionic migration process and yields a predictable formation and dissolution process of the conductive filament. The nanocone-array-based RRAM device provides a new and feasible method to control the conductive filament growth reliably, which paves the way for memristor development.