Switching Dynamics of Ag-Based Filamentary Volatile Resistive Switching Devices—Part II: Mechanism and Modeling

Abstract

Understanding the switching mechanism of the volatile resistive switching random access memory (RRAM) device is important to harness its characteristics and further enhance its performance. Accurate modeling of its dynamic behavior is also of deep value for its applications both as selector and as short-term memory synapse for future neuromorphic applications operating in temporal domain. In this work, we investigate the switching and retention (relaxation) processes of the Ag-based metallic filamentary volatile resistive switching devices. We find that the switching process can be modeled by the ionic drift under electric field, while the retention process can be modeled by the ionic diffusion along the filament surface driven by the gradient of surface atomic concentration. Through further theoretical analysis, we also find that the ionic drift and ionic diffusion can be unified within the general Einstein relation. To confirm this relation, we collect ionic mobility and diffusivity data from the literature using the switching and retention model. Finally, we show that the read voltage dependent retention time can be explained by the competition between the ionic drift and diffusion flux.

Effect of the Threshold Kinetics on the Filament Relaxation Behavior of Ag‐Based Diffusive Memristors

“…In the experiments, the filament's strength was modified qualitatively by varying the programming current through a transistor. [50,51] On the other hand, the dependence of t set on the external bias has been shown in multiple publications and, yet, lack to make connections with the t r . [52][53][54] For a wide utilization of v-ECM devices in the emerging field of neuromorphic computation [55][56][57][58] understanding and control of the switching kinetics is of utmost importance.…”

Ferroelectric-based synapses and neurons for neuromorphic computing

“…The latter approach also results in a very high on/off ratio of 10 7 [39], which is uncommon for ferroelectric devices. The exploitation of the migration of silver ions is also an element of novelty for ferroelectric devices, whereas it was already reported in some filamentary oxide-based resistive switching devices [45,46] used, as an example, for a retina-inspired artificial vision system [47].…”

Memtransistor Devices Based on MoS2Multilayers with Volatile Switching due to Ag Cation Migration

“…Similar to CBRAM devices, t ret shows a relatively wide dispersion, as also indicated by the cumulative distributions in Figure 4c. [ 39 ] The median time of the retention time is about 0.1 s with a weak dependence on I C where a higher I C results in slightly longer retention. This type of behavior was previously observed in CBRAM devices and can be explained by the dependence of diffusion rate on the surface curvature.…”