Picosecond Time-Scale Resistive Switching Monitored in Real-Time

TL;DR

This study demonstrates that resistive switching in tantalum pentoxide memristors can occur on a picosecond timescale, highlighting the potential for ultra-fast memory devices and the importance of thermal effects in high-frequency applications.

Contribution

It provides the first real-time experimental evidence of picosecond-scale resistive switching in memristors and analyzes the mechanisms limiting switching speed.

Findings

Set switching occurs at picosecond timescale, limited by bandwidth.

Reset transition duration exceeds voltage pulse, dominated by thermal diffusion.

Thermal effects are crucial for high-frequency memristor design.

Abstract

The resistance state of filamentary memristors can be tuned by relocating only a few atoms at interatomic distances in the active region of a conducting filament. Thereby the technology holds promise not only in its ultimate downscaling potential and energy efficiency but also in unprecedented speed. Yet, the breakthrough in high-frequency applications still requires the clarification of the dominant mechanisms and inherent limitations of ultra-fast resistive switching. Here we investigate bipolar, multilevel resistive switchings in tantalum pentoxide based memristors with picosecond time resolution. We experimentally demonstrate cyclic resistive switching operation due to 20 ps long voltage pulses of alternating polarity. Through the analysis of the real-time response of the memristor we find that the set switching can take place at the picosecond time-scale where it is only compromised by the bandwidth limitations of the experimental setup. In contrast, the completion of the reset transitions significantly exceeds the duration of the ultra-short voltage bias, demonstrating the dominant role of thermal diffusion and underlining the importance of dedicated thermal engineering for future high-frequency memristor circuit applications.