On the origin of resistive switching volatility in Ni/TiO2/Ni stacks

Abstract

Resistive switching (RS) and Resistive Random Access Memories (ReRAMs) that exploit it have attracted huge interests for next generation non volatile memory (NVM) applications, also thought to be able to overcome flash memories limitations when arranged in crossbar arrays. A cornerstone of their potential success is that the RS between two different resistive states, usually High (HRS, High resistive state) and Low(LRS, Low Resistive State) is an intrinsic non-volatile phenomenon with the two states thermodynamically stable. Titanium Dioxide is one of the most common materials known to show non-volatile RS. In this paper we report the first observed volatile resistive switching (VRS) in a Titanium Dioxide thin film. The aim of this paper is to study and understand the VRS phenomenon to give an extensive picture of its underlying Physics. A possible exploitation of the VRS could be in access devices in ReRAM crossbar arrays.

Sub 100 nW Volatile Nano-Metal-Oxide Memristor as Synaptic-Like Encoder of Neuronal Spikes

“…The focal point for building on the present work is to push the scaling limits for the employed devices towards deep-submicron arrays 47 , along with optimised spike-detection capability. We note that the use of alternative or engineered materials as the devices' active cores could allow tuning the volatile characteristics of devices 40 and in turn the self-reset achieved by the spike-detector. On the other hand, these parameters will also crucially depend upon the specific application under study, accounting for the sensitivity required for a particular application.…”

“…In this work we advance on our previous findings by exploiting an often overlooked crucial property of memristive devices that is 'volatility' 37,38,39,40,41 . This approach recalls the way of operation of biological synapses that translate spiking frequency in gradual changes of postsynaptic conductance subject to a continuous self-resetting process 38,42 .…”

Mesoscale Confinement Effects and Emergent Quantum Interference in Titania Antidot Thin Films

“…Volatile hysteresis is commonly observed in resistive switching materials wherein conductive filaments formed under applied bias are unstable, due to enhanced diffusion of ions and oxygen vacancies as a result of the electrode design. 32,33 The I−V curves shown in Figure 2b were recorded for an antidot film: three successive I−V curves are shown, and it can be seen that the resistance does not decrease upon repeated biasing, indicating a lack of the electroforming. In addition, no hysteresis is seen.…”

“…Thus, in the continuous films the formation of stable regions of increased conductivity, referred to as electroforming, is limited by the electrode geometry. Volatile hysteresis is commonly observed in resistive switching materials wherein conductive filaments formed under applied bias are unstable, due to enhanced diffusion of ions and oxygen vacancies as a result of the electrode design. , …”

Resistive switching and synaptic learning performance of a TiO2 thin film based device prepared by sol–gel and spin coating techniques

“…It is already known that the top electrode and interaction between the top electrodes and the semiconductor materials affect the performance of resistive switching devices [30]. Different electrodes, such as Ni/TiO 2 /Cu [31], Au/TiO 2 /Ti [32], and Ni/TiO 2 /Ni [33], have been used to fabricate the devices. It is also well known that electrode materials can affect the resistive switching characteristics of TiO 2 thin films based on resistive switching devices [34].…”