Bipolar Switching Characteristics of Transparent WOX-Based RRAM for Synaptic Application and Neuromorphic Engineering

Abstract

In this work, we evaluate the resistive switching (RS) and synaptic characteristics of a fully transparent resistive random-access memory (T-RRAM) device based on indium-tin-oxide (ITO) electrodes. Here, we fabricated ITO/WOX/ITO capacitor structure and incorporated DC-sputtered WOX as the switching layer between the two ITO electrodes. The device shows approximately 77% (including the glass substrate) of optical transmittance in visible light and exhibits reliable bipolar switching behavior. The current-voltage (I–V) curve is divided into two types: partial and full curves affected by the magnitude of the positive voltage during the reset process. In the partial curve, we confirmed that the retention could be maintained for more than 104 s and the endurance for more than 300 cycles could be stably secured. The switching mechanism based on the formation/rupture of the filament is further explained through the extra oxygen vacancies provided by the ITO electrodes. Finally, we examined the responsive potentiation and depression to check the synaptic characteristics of the device. We believe that the transparent WOX-based RRAM could be a milestone for neuromorphic devices as well as future non-volatile transparent memory.

Analog Resistive Switching and Artificial Synaptic Behavior of ITO/WOX/TaN Memristors

“…Likewise, the green and pink doublets correspond to the W 5+ oxidation state and the W 4+ oxidation state, respectively. The spectrum of O 1s has doublet peaks, of which one is oxygen deficiency (532.08 eV) and the other is W-O bonding (531.21 eV) [ 35 ].…”

“…Moreover, the cost and commercial availability should be considered when choosing materials for the RRAM. In addition, if indium tin oxide (ITO) is selected as an electrode, the device can be employed in light-based applications, such as transparent memory [ 35 ], photodetectors [ 36 ], and displays, owing to its transparency [ 37 ].…”

Resistive Switching Property of Raw Organic Cow Milk for Memory Application

“…Despite its low (≥10) I ON /I OFF ) ratio, this device has a lower switching voltage than other organic ReRAM devices, but its endurance of only 30 cycles is a drawback for non-volatile memory applications. Future electronic gadgets, on the other hand, appear to be flexible [15], transparent [15,16], and transient [17]. Yalagala et al reported on the rapid (<4 s) dissolving of a ReRAM device with a MgO-PVP-Ge active layer and Ag and ITO electrodes [17].…”

Enhanced linear and symmetric synaptic weight update characteristics in a Pt/p-LiCoOx/p-NiO/Pt memristor through interface energy barrier modulation by Li ion redistribution

“…To date, RRAM devices with a variety of oxides have been researched for synaptic device application, such as HfO 2 , 13–15 Ta 2 O 3 , 16–18 WO x , 19–21 TiO 2 , 22–24 CeO 2 , 7,25,26 ZnO, 27–29 NiO, 30–32 SrFeO x , 33 and PCMO. 34,35 With respect to the resistance change mechanism, filamentary-type CBRAM and VCM suffer from a non-linear, digital-type and asymmetric resistance change with a large device-to-device variation due to the abrupt and stochastic nature of filament formation.…”