Enhanced non-volatile resistive switching performance through ion-assisted magnetron sputtering of TiN bottom electrodes

Emerging non-volatile memristor-based memories with resistive switching (RS) materials are being widely researched as promising contenders for the next generation of data storage and neuromorphic technologies. Titanium nitride (TiNx) is a common industrial-friendly electrode system for RS; however, the precise TiNx properties required for optimum RS performance is still lacking. Herein, using ion-assisted DC magnetron sputtering, we demonstrate the key importance not only of engineering the TiNx bottom electrodes to be dense, smooth, and conductive, but also understoichiometric in N. With these properties, RS in HfO2-based memristive devices is shown to be optimised for TiN0.96. These devices have switching voltages ≤ ±1 V with promising device-to-device uniformity, endurance, memory window of ~40, and multiple non-volatile intermediate conductance levels. This study highlights the importance of precise tuning of TiNx bottom electrodes to achieve robust performance of oxide resistive switching materials.