Al filament-induced unipolar resistive switching in sputtered Al-rich AlN memristors with low operating voltage and high memory window

Abstract

Aluminum nitride (AlN) films were deposited on W/Ti/SiO₂/Si substrates using magnetron sputtering to fabricate AlN-based resistive random-access memory (RRAM) devices. By modulating the nitrogen-to-argon ratio (N₂/Ar) to form Al-rich (non-stoichiometric) AlN films, we achieved regulated unipolar RRAM devices with low set voltages (∼1 V) and reset voltages (∼0.5 V), exhibiting a significant memory window exceeding 10⁵ and retention time of ∼10³ s. The underlying mechanisms of resistive switching were explored through the analysis of the electrical performance, X-ray photoelectron spectroscopy (XPS) characterization, a variable temperature test and conduction mechanism studies. These analyses confirm that the electroformation of conductive filaments within Al-rich AlN films is responsible for the observed unipolar switching behavior. The fabricated unipolar memristors with low voltage and high on/off ratio hold great potential for future high-density multi-level arrays and low-voltage RRAM devices, offering promising prospects for efficient computing.