Observation of electric-field induced Ni filament channels in polycrystalline NiOx film

Park, Gyeong‐Su; Li, Xiang-Shu; Kim, Dong-Chirl; Jung, Ranju; Lee, Myoung-Jae; Seo, Sunae

doi:10.1063/1.2813617

Cited by 234 publications

(166 citation statements)

References 21 publications

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“…2c reached B1 Â 10 5 A cm À 2 . This current density is large enough to induce a thermally assisted electromigration 30,31 of oxygen vacancies into the insulating tantalum oxide clusters caused by the accompanying Joule heating effect 32,33 at the Pt/SiO 2 interface. This result suggests the possibility that the filamentary channels consisting of the metastable phase TaO 1 À x (ref.…”

Section: Resultsmentioning

confidence: 99%

In situ observation of filamentary conducting channels in an asymmetric Ta2O5−x/TaO2−x bilayer structure

et al. 2013

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Electrically induced resistive switching in metal insulator-metal structures is a subject of increasing scientific interest because it is one of the alternatives that satisfies current requirements for universal non-volatile memories. However, the origin of the switching mechanism is still controversial. Here we report the fabrication of a resistive switching device inside a transmission electron microscope, made from a Pt/SiO 2 /a-Ta 2 O 5 À x /a-TaO 2 À x /Pt structure, which clearly shows reversible bipolar resistive switching behaviour. The currentvoltage measurements simultaneously confirm each of the resistance states (set, reset and breakdown). In situ scanning transmission electron microscope experiments verify, at the atomic scale, that the switching effects occur by the formation and annihilation of conducting channels between a top Pt electrode and a TaO 2 À x base layer, which consist of nanoscale TaO 1 À x filaments. Information on the structure and dimensions of conductive channels observed in situ offers great potential for designing resistive switching devices with the high endurance and large scalability.

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Section: Resultsmentioning

confidence: 99%

In situ observation of filamentary conducting channels in an asymmetric Ta2O5−x/TaO2−x bilayer structure

et al. 2013

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“…Most of the existing theories of RS phenomenon are widely based on dynamic percolation model, e.g. forming and rupturing of conduction filaments [4][5][6][7] or on the migration of oxygen vacancies. [8][9][10] Recently, a new mechanism of RS based on self-trapped electrons and holes has been proposed.…”

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confidence: 99%

Magnetic field control of hysteretic switching in Co/Al2O3 multilayers by carrier injection

et al. 2011

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We propose a theoretical model of magnetic field dependence of hysteretic switching in magnetic granular system. The model is based on the self-trapped electrons mechanism. Our calculations show that the switching voltage may be significantly decreased with increasing the magnetic field. The underlying mechanism is the influence of the magnetic field on electron occupation of the conduction band, which depends on the materials used in magnetic granular system, concentration of magnetic granules in the insulating matrix, applied voltage, and the charge accumulation on the granules. We support our theoretical calculations by measuring the magnetic field dependence of resistive switching behaviour in Co/Al2O3 granular multilayers. Our experimental results are in qualitative agreement with the proposed theory

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“…22 The resistivity around the grain boundary is expected to be low, and this was experimentally confirmed by means of in-situ TEM. 42 Formation of conductive filaments and further ReRAM switching would preferentially occur around the grain boundaries.…”

Section: A Forming Power and The Bridge Sizementioning

confidence: 88%

“…There have been some attempts to observe and analyze the filaments. [22][23][24][25] They were mainly ex-situ experiments after the resistive switching, and exploration of the tiny filaments seems hard because the filament formation occurs randomly in the device area. 24 More direct information about the filaments can be accumulated by dynamically observing the switching processes.…”

Section: Introductionmentioning

confidence: 99%

In-situ transmission electron microscopy of conductive filaments in NiO resistance random access memory and its analysis

Fujii

Arita

Hamada

et al. 2013

Journal of Applied Physics

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We used thermal oxidization at various temperatures to prepare NiO/Pr-Ir for use in resistance random access memory (ReRAM) samples. In-situ transmission electron microscopy (TEM) was used to investigate the forming process of these ReRAM samples, where a needle-shaped top electrode of Pt-Ir was attached to the NiO/Pt-Ir ReRAM layer. The forming voltage initializing the NiO layer increased at an oxidization temperature of between 200 and 400 C. In this process, conductive bridges, which are thought to be conductive filaments of a ReRAM, appeared, and their sizes showed a correlation with the injection power. It was as small as about 300 nm 2 when the injection power was 10 À6 W. Energy dispersive X-ray spectroscopy was used to analyze the bridge, and it was experimentally confirmed that the oxygen content of the bridge was lower than that of the initial NiO layer. However, these bridges in the low resistance state did not show further ReRAM switching to the high resistance state inside of a TEM instrument. To check the reason of this result, we investigated samples outside of the TEM instrument, which had similar geometry to that of TEM specimens. They showed the ReRAM switching in air ambient but not in vacuum. Combining these results inside and outside of the TEM instrument, it can be concluded that the existence of oxygen around the conductive filament plays an important role. This supports the filament redox model on the ReRAM operation. V C 2013 American Institute of Physics.

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Observation of electric-field induced Ni filament channels in polycrystalline NiOx film

Cited by 234 publications

References 21 publications

In situ observation of filamentary conducting channels in an asymmetric Ta2O5−x/TaO2−x bilayer structure

In situ observation of filamentary conducting channels in an asymmetric Ta2O5−x/TaO2−x bilayer structure

Magnetic field control of hysteretic switching in Co/Al2O3 multilayers by carrier injection

In-situ transmission electron microscopy of conductive filaments in NiO resistance random access memory and its analysis

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