Tuning Memristivity by Varying the Oxygen Content in a Mixed Ionic–Electronic Conductor

Maas, Klaasjan; Villepreux, Edouard; Cooper, David; Salas‐Colera, Eduardo; Rubio-Zuazo, J.; Castro, Germán R.; Renault, O.; Jiménez, Carmen; Roussel, Hervé; Mescot, Xavier; Rafhay, Quentin; Boudard, Michel; Burriel, Mónica

doi:10.1002/adfm.201909942

Cited by 12 publications

(12 citation statements)

References 34 publications

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“…In electrochemical metallization memories, cations from an active electrode migrate reversibly in an insulating matrix, reaching the inert electrode and leading to a change in resistance. In valence change memories (VCMs) with electrode/oxide/electrode configuration, where the oxide can be insulating, such as HfO2, [3] TaOx, [4,5] SrTiO3, [6] or semiconducting, [7] such as LaMnO3, [8] or La2NiO4, [9][10][11] the resistance is modified by the drift of oxygen ions (or oxygen vacancies) and the concomitant local valence change of the cationic sublattice. Nonetheless, in many cases electronic and ionic effects interplay to give raise to the memristive response.…”

Section: Introductionmentioning

confidence: 99%

Structural Defects Improve the Memristive Characteristics of Epitaxial La_0.8Sr_0.2MnO₃‐Based Devices

Moncasi

Lefèvre

Villeger

et al. 2022

Adv Materials Inter

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of Moore's law in mind, industry and academia moved the focus to new approaches and alternative materials. In this scenario, resistive random access memories (RRAM) are considered promising candidates for the next generation of nonvolatile memories, due to their fast writing speed, high storage density, high endurance, long retention times, and low energy consumption. [1] By applying an electric stimulus, these devices exhibit a reversible change of resistance retained under zero-field conditions, and hence high and low resistance states (HRS and LRS, respectively) can be defined. In recent years, a great effort has been carried out to explain the origin of the effective change in resistance, and a wide range of possible mechanisms have been reported in the literature. [1,2] Some of the switching mechanisms rely on purely electronic effects, such as charge-trapping at an interface, modification of a Schottky barrier, or changes induced by electronic charge in strongly correlated electron systems of oxides, which can lead to metal-insulator transitions (MIT). On the other hand, ionic transport (drift) has also been reported as a mechanism able to induce a change of resistance in memristive devices. In electrochemical metallization memories, cations from an active electrode migrate reversibly in an insulating matrix, reaching the inert electrode and leading to a change in resistance. In valence change memories (VCMs) with electrode/oxide/electrode configuration, where the oxide can be insulating, such as HfO 2 , [3] TaO x , [4,5] SrTiO 3 , [6] or semiconducting, [7] such as LaMnO 3 , [8] or La 2 NiO 4 , [9][10][11] the resistance is modified by the drift of oxygen ions (or oxygen vacancies) and the concomitant local valence change of the cationic sublattice. Nonetheless, in many cases electronic and ionic effects interplay to give raise to the memristive response. [12,13] The switching event in VCMs can take place at different scales and the memories can be classified as: i) filamentary, where the change of resistance and migration of oxygen takes place in a very localized region, ii) interface-type, where the mechanism occurs at the electrode/oxide interface, [2] or iii) volume-type, which can be considered an extension of the interface-type where eventually the whole volume of the oxide is involved in the change of resistance. [14] Although so far most of the technological effort has been devoted to filamentary-type memories, these devices suffer from strong cycle-to-cycle and cell-to-cell variability. The variability has been associated to the electroforming step, and Interface-type valence change memories (VCMs) are exciting candidates for multilevel storage in resistive random access memories (RRAM) and as artificial synapses for neuromorphic computing. Several materials have been proposed as VCM candidates and, depending on the materials and electrodes of choice, different switching mechanisms take place leading to the change in resistance. Here, the focus is on La 0.8 Sr 0.2 MnO 3-δ (LSM) perovskite and, par...

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Section: Introductionmentioning

confidence: 99%

Structural Defects Improve the Memristive Characteristics of Epitaxial La_0.8Sr_0.2MnO₃‐Based Devices

Moncasi

Lefèvre

Villeger

et al. 2022

Adv Materials Inter

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“…Point defects such as oxygen vacancies play an important role in memristive devices. [1][2][3][4] Particularly in devices comprising thin films, these materials operate under high electric fields (on the order of megavolt per centimeter). Recent studies have shown DOI: 10.1002/advs.202104476 that polarization of point defects under such high electric fields can strongly impact defect formation, [5] transport, [6] and distribution, as well as dielectric response, [7] which are integral to device performance.…”

Section: Introductionmentioning

confidence: 99%

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO₃ Perovskites

et al. 2021

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Polarization of ionic and electronic defects in response to high electric fields plays an essential role in determining properties of materials in applications such as memristive devices. However, isolating the polarization response of individual defects has been challenging for both models and measurements.Here the authors quantify the nonlinear dielectric response of neutral oxygen vacancies, comprised of strongly localized electrons at an oxygen vacancy site, in perovskite oxides of the form ABO 3 . Their approach implements a computationally efficient local Hubbard U correction in density functional theory simulations. These calculations indicate that the electric dipole moment of this defect is correlated positively with the lattice volume, which they varied by elastic strain and by A-site cation species. In addition, the dipole of the neutral oxygen vacancy under electric field increases with increasing reducibility of the B-site cation. The predicted relationship among point defect polarization, mechanical strain, and transition metal chemistry provides insights for the properties of memristive materials and devices under high electric fields.

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“…This interlayer acts as an oxygen getter or oxygen reservoir and plays a key role in the memristive properties of the given device. [21][22][23] A vertical configuration is commonly used for memristors due to its reduced dimensions, compactness, and easiness for ReRAM devices fabrication, as well as compatibility for integration in cross-bar array architectures. [24] Nevertheless, given the small series resistance of the memristive layer, in particular for semiconducting oxides, which results from low film thickness (between a few nm to a few tens of nm), to avoid the device breakdown, the electrical current density should be carefully controlled by the current compliance.…”

Section: Introductionmentioning

confidence: 99%

La₂NiO_4+δ‐Based Memristive Devices Integrated on Si‐Based Substrates

Khuu

Lefèvre

Jiménez

et al. 2022

Adv Materials Technologies

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Valence Change Memories, in which internal redox reactions control the change in resistance are promising candidates for resistive random access memories (ReRAMs) and neuromorphic computing elements. In this context, La2NiO4+δ (L2NO4), a mixed ionic-electronic conducting oxide, well known for its highly mobile oxygen interstitial ions, emerges as a potential switching material for novel L2NO4-based memristive devices. However, their integration in complementary metal oxide semiconductor (CMOS) technology still has to be demonstrated, as the major focus of previous studies has been carried out on epitaxial films grown on single crystals. In this work, we present the optimization of the deposition temperature and precursor solution composition, allowing to obtain high quality polycrystalline L2NO4 thin films grown by metal organic chemical vapour deposition on a platinized silicon substrate, and to use these films to build memristive devices in vertical configuration with Ti top electrodes. A bipolar analog-type transition in resistance can be achieved in Ti/L2NO4/Pt memristive devices. While the "forming" process required for the devices based on non-optimized L2NO4 thin films is considered as a drawback, the Ti/optimized L2NO4/Pt devices are forming-free and exhibit a good cyclability.These results prove the switching response of L2NO4-based devices in vertical configuration for the first time.

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Tuning Memristivity by Varying the Oxygen Content in a Mixed Ionic–Electronic Conductor

Cited by 12 publications

References 34 publications

Structural Defects Improve the Memristive Characteristics of Epitaxial La_0.8Sr_0.2MnO₃‐Based Devices

Structural Defects Improve the Memristive Characteristics of Epitaxial La_0.8Sr_0.2MnO₃‐Based Devices

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO₃ Perovskites

La₂NiO_4+δ‐Based Memristive Devices Integrated on Si‐Based Substrates

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Tuning Memristivity by Varying the Oxygen Content in a Mixed Ionic–Electronic Conductor

Cited by 12 publications

References 34 publications

Structural Defects Improve the Memristive Characteristics of Epitaxial La0.8Sr0.2MnO3‐Based Devices

Structural Defects Improve the Memristive Characteristics of Epitaxial La0.8Sr0.2MnO3‐Based Devices

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO3 Perovskites

La2NiO4+δ‐Based Memristive Devices Integrated on Si‐Based Substrates

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Structural Defects Improve the Memristive Characteristics of Epitaxial La_0.8Sr_0.2MnO₃‐Based Devices

Structural Defects Improve the Memristive Characteristics of Epitaxial La_0.8Sr_0.2MnO₃‐Based Devices

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO₃ Perovskites

La₂NiO_4+δ‐Based Memristive Devices Integrated on Si‐Based Substrates