Reset-First and Multibit-Level Resistive-Switching Behavior of Lanthanum Nickel Oxide (LaNiO3−x) Thin Films

Abstract

The resistive random-access memory (RRAM) with multi-level storage capability has been considered one of the most promising emerging devices to mimic synaptic behavior and accelerate analog computations. In this study, we investigated the reset-first bipolar resistive switching (RS) and multi-level characteristics of a LaNiO3−x thin film deposited using a reactive magnetron co-sputtering method. Polycrystalline phases of LaNiO3 (LNO), without La2O3 and NiO phases, were observed at similar fractions of Ni and La at a constant partial pressure of oxygen. The relative chemical proportions of Ni3+ and Ni2+ ions in LaNiO3−x indicated that it was an oxygen-deficient LaNiO3−x thin film, exhibiting RS behavior, compared to LNO without Ni2+ ions. The TiN/LaNiO3−x/Pt devices exhibited gradual resistance changes under various DC/AC voltage sweeps and consecutive pulse modes. The nonlinearity values of the conductance, measured via constant-pulse programming, were 0.15 for potentiation and 0.35 for depression, indicating the potential of the as-fabricated devices as analog computing devices. The LaNiO3−x-based device could reach multi-level states without an electroforming step and is a promising candidate for state-of-the-art RS memory and synaptic devices for neuromorphic computing.

Synthesis of LaXO3 (X = Fe, Mn, Cr, Ni) Thin Films Using a Simple Spin Coating Set-Up for Resistive Switching Memory Devices

“…Moreover, Wan Jing et al [7] investigated the RS behavior of PLD-fabricated LaCrO 3 thin films, revealing unipolar switching behavior with a high resistance ratio and excellent endurance and retention characteristics. Additionally, T Kim et al [20] showed that the fabricated TiN/LaNiO 3−x /Pt RRAM devices exhibited reset-first RS behavior and gradual resistance changes under AC pulse application, making them suitable for low-power synaptic devices in neuromorphic computing.…”