Interfacial Metal–Oxide Interactions in Resistive Switching Memories

Cho, Deok‐Yong; Luebben, Michael; Wiefels, Stefan; Lee, Kug‐Seung; Valov, Ilia

doi:10.1021/acsami.7b02921

Cited by 108 publications

(106 citation statements)

References 47 publications

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“…Such kind of observation of device failure with bubble formation is also reported in Hf/HfO 2 /Pt resistive cells. 29 To understand the increase in current with successive voltage pulses with pulse interval of 2 s or less, we analysed the decay of current after every pulse of amplitude 12 V and width 100 ms, Fig. 5(a) Where, I 0 is the steady state current, A is constant and τ is the relaxation time.…”

Section: Resultsmentioning

confidence: 99%

NbOx based memristor as artificial synapse emulating short term plasticity

Deswal

Kumar

2019

AIP Advances

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Memristors can mimic the functions of biological synapse, where it can simultaneously store the synaptic weight and modulate the transmitted signal. Here, we report Nb/Nb 2 O 5 /Pt based memristors with bipolar resistive switching, exhibiting synapse like property of gradual and continuously change of conductance with subsequent voltage signals. Mimicking of basic functions of remembering and forgetting processes of biological brain were demonstrated through short term plasticity, spike rate dependent plasticity, paired pulse facilitation and post-titanic potentiation. The device layer interface tuning was shown to affect the device properties shift from digital to analog behaviour. Demonstration of basic synaptic functions in the NbOx based devices makes them suitable for neuromorphic applications.

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Section: Resultsmentioning

confidence: 99%

NbOx based memristor as artificial synapse emulating short term plasticity

Deswal

Kumar

2019

AIP Advances

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“…www.advelectronicmat.de density, [10] (ii) different bond strength [16] of the absorbed moisture to the oxide matrix, and (iii) different interface properties [17,18] (resistance at the electrode/oxide interface or the overpotential for the electrochemical electrode reaction).…”

Section: Resultsmentioning

confidence: 99%

Processes and Effects of Oxygen and Moisture in Resistively Switching TaO_x and HfO_x

Lübben

Wiefels

Waser

et al. 2017

Adv Elect Materials

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but also for being building units for neuromorphic applications and non-von Neumann computing. [1,2] ReRAMs consist of a simple metal-solid electrolyte-metal stack where the information is stored as electronic resistance state of the electrochemical cell. [3] By applying a voltage of different polarity and/or magnitude, formation or rupture of a conductive filament is induced, leading to a nonvolatile low-resistive ON state (also denoted as LRS) or high-resistive OFF state (HRS), respectively. ReRAMs have the advantages of showing low power consumption, fast switching times (down to hundreds of picoseconds), and high endurance and retention. Depending on the working principle, ReRAMs are classified into valence change memory (VCM), electrochemical metallization memory (ECM), or thermochemical memory (TCM). While TCM devices are not of current interest for applications, ECM and VCM show particular promises. The functionality of both types relies on redox reactions and movement of ions and electrons within the solid electrolyte. [3,4] In the case of ECM, the active electrode is (partially) oxidized and metal cations drift within the electrolyte toward the counter electrode where they are reduced back to metal. Due to the high electric fields and high current densities the reduced metallic phase is formed as a tiny (few nm in diameter) filament. [2] The mechanism of VCM devices is considered to be based on a localized partial reduction of the solid electrolyte leading to an oxygen deficient, electrically conductive, filament. Originally the reduction was explained solely by loss of oxygen ions, i.e., formation of additional oxygen vacancies V O •• with a charge, compensated by electrons. However, new studies have demonstrated that the cations in such oxides are often mobile and can participate in the switching process as well. [5,6] Applying a voltage of opposite polarity, the formed filament is partially reoxidized within a thin region facing the high work function metal electrode, defining the OFF state. By modulation of the Schottky barrier at this interface reversible switching between the LRS and HRS is possible. [7] The mechanistic details on the electroforming and switching are still under discussion and despite many studies were performed on this topic, no consensus is reached till today. One of the most recent achievements was the experimental verification that redox processes are preceding and directly responsible for the forming itself. [6] Foreign components such as dopants and impurities in molecular or ionic form may significantly influence forming/switching processes in redox-based memories. This work presents a systematic study and discussion on effects of oxygen and moisture in Ta 2 O 5 and HfO 2 thin films, being two of the most used materials for redox-based resistively switching random access memories. Whereas oxygen is found to not affect the device behavior, the presence of moisture profoundly influences it. It plays a crucial role for the counter electrode reaction, providing additional charg...

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“…The nanobattery effect is often modulated by interface interactions between the electrode and SiO 2 . It has been found that, irrespective of the macroscopic thermodynamic predictions, oxide thin films always form at the interface between active metals and SiO 2 . This oxide film, for example in the case of Cu/SiO 2 , provides an important source of Cu ions.…”

Section: Extrinsic Switching: Electrochemical Reactions and Ecm Resismentioning

confidence: 99%

Silicon Oxide (SiO_x): A Promising Material for Resistance Switching?

et al. 2018

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Interest in resistance switching is currently growing apace. The promise of novel high-density, low-power, high-speed nonvolatile memory devices is appealing enough, but beyond that there are exciting future possibilities for applications in hardware acceleration for machine learning and artificial intelligence, and for neuromorphic computing. A very wide range of material systems exhibit resistance switching, a number of which-primarily transition metal oxides-are currently being investigated as complementary metal-oxide-semiconductor (CMOS)-compatible technologies. Here, the case is made for silicon oxide, perhaps the most CMOS-compatible dielectric, yet one that has had comparatively little attention as a resistance-switching material. Herein, a taxonomy of switching mechanisms in silicon oxide is presented, and the current state of the art in modeling, understanding fundamental switching mechanisms, and exciting device applications is summarized. In conclusion, silicon oxide is an excellent choice for resistance-switching technologies, offering a number of compelling advantages over competing material systems.

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Interfacial Metal–Oxide Interactions in Resistive Switching Memories

Cited by 108 publications

References 47 publications

NbOx based memristor as artificial synapse emulating short term plasticity

NbOx based memristor as artificial synapse emulating short term plasticity

Processes and Effects of Oxygen and Moisture in Resistively Switching TaO_x and HfO_x

Silicon Oxide (SiO_x): A Promising Material for Resistance Switching?

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Interfacial Metal–Oxide Interactions in Resistive Switching Memories

Cited by 108 publications

References 47 publications

NbOx based memristor as artificial synapse emulating short term plasticity

NbOx based memristor as artificial synapse emulating short term plasticity

Processes and Effects of Oxygen and Moisture in Resistively Switching TaOx and HfOx

Silicon Oxide (SiOx): A Promising Material for Resistance Switching?

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Product

Resources

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Processes and Effects of Oxygen and Moisture in Resistively Switching TaO_x and HfO_x

Silicon Oxide (SiO_x): A Promising Material for Resistance Switching?