Nitrogen-induced filament confinement strategy for implementing reliable resistive switching performance in a-HfOx memristors

Abstract

Hafnium oxide (HfOx) films are highly valued as functional layers in nonvolatile resistive switching (RS) memristors due to their scalability, compatibility with CMOS technology, and high dielectric constant. However, the low reliability of HfOx-based memristors is the key factor hindering their widespread practical applications. Herein, amorphous HfOx (a-HfOx) films are used as the switching layers to construct memristors, and the nitrogen treatment strategy is employed to enhance the switching characteristics. All the fabricated Al/a-HfOx/ITO memristors demonstrate bipolar digital RS behaviors, and specifically, the 500 °C-treated a-HfOx device exhibits highly reliable RS performance, including low cycle-to-cycle variability, concentrated distributions and low operating voltages, long-term retention capacity (>104 s), and good cycle endurance (>200 cycles). The mechanisms and physical models for enhanced switching performance are thoroughly elucidated, revealing that the formation of stable oxygen vacancy–dinitrogen complexes confines the conductive filament path and significantly reduces filament randomness during formation and rupture. This work renders an effective material engineering strategy for widening a path toward designing highly reliable nonvolatile data storage devices with striking switching performances.