A Non-Invasive Approach to the Resistive Switching Physical Model of Ultra-Thin Organic-Inorganic Dielectric-based ReRAM

Abstract The extremely reduced thickness of the recently introduced ultra-thin (< 5 nm) organic-inorganic hybrid dielectric-based ReRAM hinders their processability through material characterization techniques. But the attractiveness of these devices as the next-generation non-volatile memory requires a deep understanding of the resistive switching (RS) dynamics in the hybrid dielectric layer. Moreover, the poor uniformity in key switching parameters still persistent in ReRAMs impedes any trends to be clearly defined through electrical characterization. This work uses electrical manipulation through a ramped-pulse series (RPS) method to improve the voltage and resistance fluctuations in the reset process of ultra-thin Al/Hf-hybrid/Ni devices at different pulse voltage amplitude, pulse width, and temperature conditions. By analyzing the electrical behavior of the device under these conditions, a novel and detailed physical model describing the operating mechanism is proposed. The coexistence in the conductive filament (CF) of a hybrid metallic portion composed of \(\text{A}\text{l}\) and \({\text{H}\text{f}}_{3}{\text{A}\text{l}}_{2}\), and an oxygen vacancy portion is confirmed. Our model emphasizes the vacancies contribution in the RS, where majority of them are generated during the CF forming process and participate to different degrees in the filament rupture of the RPS and no-RPS-processed devices via Joule heating, drift, and Fick forces. Additionally, switching failure events are explained based on the presence of an \({\text{A}\text{l}}_{2}{\text{O}}_{3}\) interlayer in the Al/Hf-hybrid interface.