Interface Engineering via MoS₂ Insertion Layer for Improving Resistive Switching of Conductive‐Bridging Random Access Memory

Abstract

Conductive‐bridging random access memory (CBRAM), dominated by conductive filament (CF) formation/rupture, has received much attention due to its simple structure and outstanding performances for nonvolatile memory, neuromorphic computing, digital logic, and analog circuit. However, the negative‐SET behavior can degrade device reliability and parameter uniformity. And large RESET current increases power consumption for memory applications. By inserting 2D material, molybdenum disulfide (MoS2), for interface engineering with the device configuration of Ag/ZrO2/MoS2/Pt, the negative‐SET behavior is eliminated, and the RESET current is reduced simultaneously. With the ion barrier property of MoS2, the CF can probably not penetrate the MoS2 layer, thus eliminating the negative‐SET behavior. And with the low thermal conductivity of MoS2, the internal temperature of the device would be relatively high at RESET, accelerating probably redox reactions. As a result, the RESET current is reduced by an order of magnitude. This interface engineering opens up a way in improving the resistive switching performances of CBRAM, and can be of great benefit to the potential applications of MoS2 in next‐generation data storage.

2D Material Based Synaptic Devices for Neuromorphic Computing

“…Besides, for the thicker MoS 2 film, a higher energy is required for penetration. [ 98 ] Similar conclusion is obtained in graphene with different sized holes. [ 99 ] The defected graphene serves as a sieve.…”

“…[ 94–95 ] These transitions are nonvolatile and lead to resistance states change, which facilitates the research of RRAM and synapse devices. [ 93,98–99 ] Besides, in 1T‐TaS 2 , due to the strong electron–electron and electron–phonon interaction, it exhibits rich phase transition with decreasing the temperature, including transition from incommensurate charge density wave (ICCDW) below 550 K to nearly commensurate charge density wave (NCCDW) around 350 K, and then from NCCDW to commensurate charge density wave (CCDW) around 180 K, which is stabilized by the Mott insulator state. [ 117 ] With decreasing temperature, lattice distortion of Ta atoms causes the formation of clusters of David stars.…”

“…The two‐terminal memristor, whose resistance state strongly depends on its past states, provides an opportunity to mimic the synaptic connections between neurons. Recently, 2D materials have been widely used to reveal the working principle of conductive filament growth and rupture in artificial synapses, [ 179–180 ] improve the performances of conventional metal oxide based memristors, [ 98–99,181–184 ] and develop various vertical memristors with fast switching speed, low threshold voltage and high electrical endurance. [ 10,47,185–192 ] Among these memristors, the sandwiched devices with the ability to hold multilevel nonvolatile states are promising for realizing artificial synaptic devices.…”

A Review of Resistive Switching Devices: Performance Improvement, Characterization, and Applications

“…For the Ag/ZrO 2 /Pt device, the negative‐SET behavior can be observed, significantly degrading device reliability and parameter uniformity (Figure 5e). [ 126 ] By inserting a MoS 2 layer between the ZrO 2 layer and the Pt electrode, the penetration of Ag filaments into the Pt electrode is prevented even under a high SET voltage. Consequently, negative‐SET behavior is eliminated, resulting in good uniformity of the SET/RESET voltage and cycle‐to‐cycle endurance (Figure 5f).…”

Memory materials and devices: From concept to application

“…ECM cells typically have abrupt SET and RESET processes, small operation voltages, fast SET/RESET, and a large ON/OFF ratio due to the fast kinetics of metal cations and high electronic conductivity of the metallic filament. However, from another point of view, the fast kinetics hinders the realization of multiple resistance levels (although current compliance can enable multiple levels, it increases circuit overhead), leads to a harmful negative‐SET phenomenon, and degrades the endurance and retention (“voltage‐time dilemma”) . And the high conductive filament results in high ON current, increasing the power consumption.…”