Bilayer Ohmic Electrode Engineering in TaOX ReRAM Devices

Abstract

$\text {TaO}_{\text {X}}$ Redox-based Random Access Memory (ReRAM) is a strong candidate to replace existing memory technologies, offering low power consumption, high endurance, and long retention. However, reducing switching energy and enhancing switching uniformity are critical for practical applications. Previous efforts to improve switching uniformity have compromised device performance, leading to low On/Off ratio or high operating voltages. In this work, $\text {TaO}_{\text {X}}$ ReRAM is engineered with bilayer ohmic electrodes (OE) and the switching mechanism for specific OE thicknesses is explored based on the switching behavior and material properties of OE. An optimized Ti(2 nm)/Ta(13 nm) bilayer OE ReRAM is presented with a reduced forming voltage, $\sim 11\times $ ( $\sim 6\times $ ) faster mean SET (RESET) switching speeds, $\sim 6\times $ lower mean switching energy and $\sim 10\times $ lower resistance drift during long switching cycles compared to its single-layer OE counterpart, without degradation in other device performance metrics.