Switching operation and degradation of resistive random access memory composed of tungsten oxide and copper investigated using in-situ TEM

Arita, Masashi; Takahashi, Akihito; Ohno, Yuichi; Nakane, Akitoshi; Tsurumaki‐Fukuchi, Atsushi; Takahashi, Yasuo

doi:10.1038/srep17103

Cited by 62 publications

(57 citation statements)

References 43 publications

(75 reference statements)

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“…Then, dissolved Ag cations migrate and form a conducting bridge between the Ag top and Pt bottom electrodes ( Figure 6). [53,54] In contrast with the formation of the conducting filament, the rupture of the same filament occurs when an external bias is applied in the opposite direction. With this thermally assisted ion hopping transport, the Ag cations migrate and reach the Pt bottom electrode, which acts as a counter electrode.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

“…With this thermally assisted ion hopping transport, the Ag cations migrate and reach the Pt bottom electrode, which acts as a counter electrode. [53] When the conducting filament grows considerably large so as to rupture with the external bias, the device cannot become insulating, resulting to a switching failure. Therefore, the formation of the conducting bridge, which consists of Ag atoms, is achieved, and the resistance of the device is changed to LRS.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

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Conducting Bridge Resistive Switching Behaviors in Cubic MAPbI₃, Orthorhombic RbPbI₃, and Their Mixtures

Lee

Choi

Jeon

et al. 2018

Adv Elect Materials

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exhibit low-operation voltages, reduced power consumption, high on/off ratios, and remarkable mechanical flexibility. [9,16] These outstanding properties are suitable for next-generation resistive switching memories. However, the present HPbased resistive switching memories have critical weaknesses, such as short endurance and poor air-stability. Even though conventional CBRAMs recorded over 10 6 cycles of endurance, halide perovskite based resistive switching devices exhibited around 10 3 cycles of endurance. [17,18] To overcome these limitations, diverse solutions have been reported. One strategy is discovering and synthesizing more stable chemical compositions of HPs. To obtain stable resistive switching properties, various compositions of HPs have been investigated and reported. [19][20][21] Another strategy is adopting a passivation layer on HP films, such as polymethyl methacrylate (PMMA), zinc oxide, and ethylene diamine, so as to isolate the films from the atmosphere and complement their defects. [22][23][24][25] The other strategy is by improving the morphology of the HP films. In this regard, solvent engineering can be employed. By dripping antisolvents, such as toluene, benzene, and chlorobenzene, and adding hydroiodic acid solution as an additive in the precursor solution of HPs, morphologically uniform and high quality HP films [26][27][28][29] can be obtained. Nevertheless, these strategies still could not provide the fundamental solutions to the degradation mechanism, in which the devices are usually stuck in low resistance states (LRS, Figure S1, Supporting Information).We have been interested in the use of HPs for resistive switching devices because HP easily changes its composition and crystalline structure by a certain tolerance factor (t) value. [30,31] The methylammonium lead iodide (MAPbI 3 ) crystalline structure is a pseudocubic structure under ambient conditions. However, the MA + cation of MAPbI 3 in BX 6 octahedral void causes a disordered structure and exhibits hysteresis, which is an important factor in the resistive switching behavior. [32,33] Hence, MAPbI 3 is weak under ambient conditions because of the volatile MA + cation. On the other hand, the RbPbI 3 crystalline structure is orthorhombic, which is extremely stable under ambient conditions because of the less volatile Rb + cation and can be stabilized as a 1DRecently, halide perovskites (HPs), which exhibit resistive switching (RS) behaviors, are proposed as a promising candidate for next-generation memory because of their low power consumption, low cost, and mechanical flexibility. However, HP-based memories have crucial problems related to short endurance and vague switching mechanism. Here, the RS behaviors of switchable methylammonium lead iodide (MAPbI 3 ) and nonswitchable rubidium lead iodide (RbPbI 3 ) mixtures are reported and it is elucidated on the source of the switching phenomena. By controlling the ratio of rubidium iodide (RbI)/ methylammonium iodide (MAI), five compositions of the mixture of RbPbI 3 and MAPbI 3 ...

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Section: Wwwadvelectronicmatdementioning

confidence: 99%

Section: Wwwadvelectronicmatdementioning

confidence: 99%

Conducting Bridge Resistive Switching Behaviors in Cubic MAPbI₃, Orthorhombic RbPbI₃, and Their Mixtures

Lee

Choi

Jeon

et al. 2018

Adv Elect Materials

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“…TEM is a microscopic imaging technique in which a beam of electrons is transmitted through an ultra-thin specimen (thickness < 100 nm) and an image is subsequently formed from the interaction between the electrons and the sample. Due to the small de Broglie wavelength of electrons, and especially thanks to recent technological advancements such as the introduction of spherical aberration correctors, state-of-the-art TEM instruments have reached unparalleled resolutions beyond the angstrom scale, making TEM one of the most powerful technologies to resolve the structural details of conducting filaments [9][10][11][12]. In addition, analytical studies of the filaments can be realized utilizing complementary techniques in TEM, such as energy dispersive X-ray spectroscopy (EDS or EDX), electron energy loss spectroscopy (EELS), and so on, providing further information about the composition and chemical states of filaments.…”

Section: Sample Structures Enabling In Situ Tem Observationsmentioning

confidence: 99%

“…Ag/a-Si(PECVD)/Pt b in situ TEM Filament [9] Ni/ZrO2/Pt -in situ TEM Filament [21] Ag/SiO2(PECVD)/p + -Si b in situ TEM Filament [14] Ag/SiO2(evaporated)/Pt b in situ TEM Filament [10] Cu/WOx/TiN -in situ TEM Filament [12] Au/SiO2(PECVD)/Ag nanoclusters/SiO2/p + -Si b in situ TEM Cluster [14] Au/SiO2(evaporated)/Ag nanoclusters/SiO2/Au b in situ TEM Cluster [10] Au/SiO2(evaporated)/Cu nanoclusters/SiO2/Au b in situ TEM Cluster [10] Au/SiO2(evaporated)/Ni nanoclusters/SiO2/Au c in situ TEM Cluster [10] Au/SiO2(evaporated)/Pt nanoclusters/SiO2/Au b in situ TEM Cluster [10] Cu/Ta2O5/Pt -ex situ TEM Filament [22] Ag/ZnO:Mn/Pt -ex situ TEM Filament [23] Ag/Ag30Ge17Se53/Pt -ex situ TEM Percolation [19] Planar Ag/H2O/Pt a SEM Filament [24] Ag/SiO2(sputtered)/Pt d ex situ TEM Filament [9] Ag/Al2O3/Pt b SEM Filament [9] Ag/Ag-PEO/Pt d SEM Filament [25] Ag/PEO/Pt b SEM Filament [25] Ag/a-Si(PECVD)/Pt b SEM Filament [9] Ag/TiO2/Pt -SEM Filament [26] Pd/SiOx(sputtered)/Pd b ex situ TEM Filament [27] Ag/PEDOT:PSS/Pt b SEM Filament [28] "-" implies the growth mode cannot be determined based on the reported results.…”

Section: Classification Of Dynamic Metal Filament Growth Modesmentioning

confidence: 99%

Probing electrochemistry at the nanoscale: in situ TEM and STM characterizations of conducting filaments in memristive devices

et al. 2017

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Correspondence to: yuchaoyang@pku.edu.cn (Y.Y.), y-taka@ist.hokudai.ac.jp (Y.T.), arita@nano.ist.hokudai.ac.jp (M.A.), m.moors@fz-juelich.de (M.M.), a.kenyon@ucl.ac.uk (A.J.K.)Abstract Memristors or memristive devices are two-terminal nanoionic systems whose resistance switching effects are induced by ion transport and redox reactions in confined spaces down to nanometre or even atomic scales. Understanding such localized and inhomogeneous electrochemical processes is a challenging but crucial task for continued applications of memristors in nonvolatile memory, reconfigurable logic, and brain inspired computing. Here we give a survey for two of the most powerful technologies that are capable of probing the resistance switching mechanisms at the nanoscaletransmission electron microscopy, especially in situ, and scanning tunneling microscopy, for memristive systems based on both electrochemical metallization and valence changes. These studies yield rich information about the size, morphology, composition, chemical state and 2 growth/dissolution dynamics of conducting filaments and even individual metal nanoclusters, and have greatly facilitated the understanding of the underlying mechanisms of memristive switching.Further characterization of cyclic operations leads to additional insights into the degradation in performance, which is important for continued device optimization towards practical applications.Resistive Random Access Memories (ReRAMs), or memristors [1], have tremendous potential for applications in nonvolatile embedded or storage class memories [2, 3], as well as in-memory logic that overcomes the von Neumann bottleneck [4]. They are also envisaged to form the basis of power-efficient neuromorphic systems by implementing plasticity similar to that of biological synapses [5]. Consequently, extensive efforts have been devoted to research into this novel class of devices, including studies of switching materials, device structures, scalability, integration, and so on.In particular, it is very important to understand the fundamental operation mechanisms of ReRAM in order to guide device-related studies. It is well known that the resistance switching effects in memristors are usually modulated by ionic transport and subsequent conducting filament formation/dissolution processes occurring at dimensions around 10 nm, and even down to atomic scales [6][7][8], hence elucidating the switching mechanisms requires advanced characterization techniques capable of resolving the nanoscale switching regions formed randomly in the devices.Here we give a survey of two of the most important technologies in understanding the switching mechanisms of ReRAMtransmission electron microscopy (TEM), especially when applied in situ, and scanning tunneling microscopy (STM). We will discuss the principles and designs behind these techniques, and show how they have furthered the understanding of the nature and dynamic evolution of conductive filaments. Finally, the remaining challenges in the understanding of memristive mechanisms w...

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“…In the D1 device, the Ir buffer layer thickness is ≈2 nm. [41] This process goes on during cycling. Therefore, the copper diffusion could not be controlled.…”

Section: Figure 2amentioning

confidence: 99%

Controlling Conductive Filament and Tributyrin Sensing Using an Optimized Porous Iridium Interfacial Layer in Cu/Ir/TiN_xO_y/TiN

Dutta

Maikap

Qiu

2018

Adv Elect Materials

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Controlling the copper (Cu) filament using an optimized porous iridium (Ir) interfacial layer thickness ranging from 2 to 20 nm in a Cu/Ir/TiNxOy/TiN resistive switching memory device is investigated for the first time. Transmission electron microscopy (TEM) shows a porous Ir layer, and X‐ray photoelectron spectroscopy (XPS) is performed to determine the Ir0, Ir3+/Ir4+ oxidation states, which are responsible for a super‐Nernstian pH sensitivity of 125.5 mV pH−1 as well as a low concentration of 1 × 10−12m tributyrin detected using a 40 nm thick Ir in Ir/TiNxOy/TiN structure. The 5 nm thick Ir layer in the Cu/Ir/TiNxOy/TiN structure shows current–voltage switching characteristics for 3000 consecutive cycles, a stable RESET voltage, a long program/erase (P/E) endurance of >109 cycles under a P/E current of 300 µA at a high speed of 100 ns, and neuromorphic phenomena compared to those of other Ir thicknesses. Cu migration into the TiNxOy oxide‐electrolyte is shown by TEM observations. The tributyrin detection ranging from 1 × 10−12 to 100 × 10−12m using a resistive switching memory device paves the way for the early diagnosis of human diseases as well as artificial intelligence applications in the near future.

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Switching operation and degradation of resistive random access memory composed of tungsten oxide and copper investigated using in-situ TEM

Cited by 62 publications

References 43 publications

Conducting Bridge Resistive Switching Behaviors in Cubic MAPbI₃, Orthorhombic RbPbI₃, and Their Mixtures

Conducting Bridge Resistive Switching Behaviors in Cubic MAPbI₃, Orthorhombic RbPbI₃, and Their Mixtures

Probing electrochemistry at the nanoscale: in situ TEM and STM characterizations of conducting filaments in memristive devices

Controlling Conductive Filament and Tributyrin Sensing Using an Optimized Porous Iridium Interfacial Layer in Cu/Ir/TiN_xO_y/TiN

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Switching operation and degradation of resistive random access memory composed of tungsten oxide and copper investigated using in-situ TEM

Cited by 62 publications

References 43 publications

Conducting Bridge Resistive Switching Behaviors in Cubic MAPbI3, Orthorhombic RbPbI3, and Their Mixtures

Conducting Bridge Resistive Switching Behaviors in Cubic MAPbI3, Orthorhombic RbPbI3, and Their Mixtures

Probing electrochemistry at the nanoscale: in situ TEM and STM characterizations of conducting filaments in memristive devices

Controlling Conductive Filament and Tributyrin Sensing Using an Optimized Porous Iridium Interfacial Layer in Cu/Ir/TiNxOy/TiN

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Conducting Bridge Resistive Switching Behaviors in Cubic MAPbI₃, Orthorhombic RbPbI₃, and Their Mixtures

Conducting Bridge Resistive Switching Behaviors in Cubic MAPbI₃, Orthorhombic RbPbI₃, and Their Mixtures

Controlling Conductive Filament and Tributyrin Sensing Using an Optimized Porous Iridium Interfacial Layer in Cu/Ir/TiN_xO_y/TiN