Compliance-Current Manipulation of Dual-Filament Switching in a Ta/Ta2O5/In−Sn−O Structure with an Ultralow Power Consumption

Abstract

A continual change in resistance plays an important role in simulating the biological synapses and an abrupt switching mode helps to store information with fast speed and low-power operation. The manipulation of dual-mode switching and comprehension of switching mechanisms, which are the key to developing multifunctional resistance random access memory devices, has made little progress due to the complexity of the influencing factors. We observe that both gradual and abrupt reset behaviors exist in the $\mathrm{Ta}/{\mathrm{Ta}}_{2}{\mathrm{O}}_{5}/\mathrm{In}\text{\ensuremath{-}}\mathrm{Sn}\text{\ensuremath{-}}\mathrm{O}$ (ITO) structure, and the utilization of various compliance currents (${I}_{\mathrm{CC}}$) can control the reset processes of the device. The difference in switching behavior is a result of the different compositions of the conductive filaments (CFs). $\mathrm{Ta}$ and oxygen-vacancy dual filaments contribute to resistive switching at low ${I}_{\mathrm{CC}}$, whereas the change in valence states of ${\mathrm{Ta}\mathrm{O}}_{x}$ dominates the formation and rupture of CFs at high ${I}_{\mathrm{CC}}$. The introduction of a thin ${\mathrm{Mo}\mathrm{S}}_{2}$ intermediate layer also leads to a transition between abrupt- and gradual-switching modes. The $\mathrm{Ta}/{\mathrm{Mo}\mathrm{S}}_{2}/{\mathrm{Ta}}_{2}{\mathrm{O}}_{5}/\mathrm{ITO}$ device exhibits digital switching behavior with ultralow power consumption. Moreover, the $\mathrm{Ta}/{\mathrm{Ta}}_{2}{\mathrm{O}}_{5}/{\mathrm{Mo}\mathrm{S}}_{2}/\mathrm{ITO}$ device with an analog reset process can be applied to realize synaptic functions.