Unveiling the hybrid filaments-induced forming-free resistive switching dynamics in Cu-doped oxygenated amorphous carbon-based memristors

Abstract Oxygenated amorphous carbon (α-C:O _x ) media in resistive memories has gained attention due to their cost-effectiveness, high resilience to external stimuli, and versatility in various applications. However, the forming process at high voltages and the low durability for α-C:O _x -based resistive memories impose limitations on their use in memory-centric computing systems. We report reliable forming-free Cu-doped α-C:O _x resistive memories (CCRMs) with multi-level properties, where resistive switching occurs via a hybrid conducting path of sp ² covalent bonds and Cu filaments. To unveil the possible forming-free dynamics, we conducted in-depth studies using bias-dependent time-of-flight secondary ion mass spectroscopy and X-ray photoelectron spectroscopy for ion depth profiles and chemical bonding states analysis, respectively. We scaled down CCRMs to ~37 nm, achieving over 10 ⁷ write/read endurance cycles and exceptional non-volatility of about 10.7 years at 85 °C. By varying reset voltage amplitudes, we achieved stable multi-level states. We demonstrated stable resistive switching in one-selector and one-resistor (1S1R) crossbar arrays with vertically stacked CCRMs and chalcogenide-based super-linear-threshold-switching selectors, confirming a readout margin of ~98.9% at ~1 terabit size. Finally, we demonstrated outstanding inference performance in binarized neural networks using 1S1R cell-based binary synapses, comparable to ideal cases. Our research is poised to provide groundbreaking advancements in carbon-based electronics.