Study of the SET switching event of VCM-based memories on a picosecond timescale

Witzleben, Moritz von; Hennen, T.; Kindsmüller, Andreas; Menzel, Stephan; Waser, Rainer; Böttger, U.

doi:10.1063/5.0003840

Cited by 25 publications

(43 citation statements)

References 49 publications

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“…We also compare the SET kinetics of the three devices on a sub-nanosecond timescale. Two of them were already published in previous studies [5], [19]. By means of the estimated effectively applied voltage, we show that the SET kinetics of all three devices depend on their feature sizes and are consequently mainly limited by the electrical charging time.…”

Section: Introductionmentioning

confidence: 53%

“…Information on the fabrication can be found in [34] and information on the SET kinetics can be found in [19]. To reduce the losses, the length of the CPW structure was reduced from 930 µm to 600 µm and the length of the tapered area was reduced to 10 µm (see Fig.…”

Section: A Devicesmentioning

confidence: 99%

“…We have recently published the SET kinetics of the Ta1 device [5] and the ones of the Ta3 device [19]. In these publications, the experimental procedures are explained explicitly.…”

Section: Set Kinetic Measurementsmentioning

confidence: 99%

“…So far, several studies have investigated the switching time at timescales below 1 ns [5], [15]- [18]. The fastest SET time within 50 ps was observed in TaO x and ZrO x [19] and the fastest RESET time within 85 ps in AlN [20]. In all of these studies, short electrical pulses were applied to VCM devices.…”

Section: Introductionmentioning

confidence: 99%

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Determining the Electrical Charging Speed Limit of ReRAM Devices

Witzleben

Walfort

Waser

et al. 2021

IEEE J. Electron Devices Soc.

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Redox-based random-access memory (ReRAM) has the potential to successfully address the technological barriers that today's memory technologies face. One of its promising features is its fast switching speed down to 50 ps. Identifying the limiting process of the switching speed is, however, difficult. At sub-nanosecond timescales three candidates are being discussed: An intrinsic limitation, being the migration of mobile donor ions, e.g. oxygen vacancies, the heating time, and its electrical charging time. Usually, coplanar waveguides (CPW) are used to bring the electrical stimuli to the device. Based on the data of previous publications, we show, that the rise time of the effective electrical stimulus is mainly responsible for limiting the switching speed at the sub-nanosecond timescale. For this purpose, frequency domain measurements up to 40 GHz were conducted on three Pt\TaOx\Ta devices with different sizes. By multiplying the obtained scattering parameters of these devices with the Fourier transform of the incoming signal, and building the inverse Fourier transform of this product, the voltage at the ReRAM device can be determined. Finally, the rise time of the voltage at the ReRAM device is calculated, which is a measure to the electrical charging time. It was shown that this rise time amounts to 2.5 ns for the largest device, which is significantly slower than the pulse generator's rise time. Reducing the device's rise time down to 66 ps is possible, but requires smaller features sizes and other optimizations, which we summarize in this paper.

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Section: Introductionmentioning

confidence: 53%

Section: A Devicesmentioning

confidence: 99%

“…We have recently published the SET kinetics of the Ta1 device [5] and the ones of the Ta3 device [19]. In these publications, the experimental procedures are explained explicitly.…”

Section: Set Kinetic Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determining the Electrical Charging Speed Limit of ReRAM Devices

Witzleben

Walfort

Waser

et al. 2021

IEEE J. Electron Devices Soc.

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“…of Oxide-Based Resistive Switching Memory scalability, fast operation, low power consumption, and high retention [3], [5]- [9]. Toward the industrial application of ReRAM, its reliability is highly relevant [10].…”

Section: Impact Of the Ohmic Electrode On The Endurancementioning

confidence: 99%

Impact of the Ohmic Electrode on the Endurance of Oxide-Based Resistive Switching Memory

Wiefels

Witzleben

Huttemann

et al. 2021

IEEE Trans. Electron Devices

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As one of the key aspects in the reliability of redox-based resistive switching memories (ReRAMs), maximizing their endurance is of high relevance for industrial applications. The major limitation regarding endurance is considered the excessive generation of oxygen vacancies during cycling, which eventually leads to irreversible RESET failures. Thus, the endurance could be increased by using combinations of switching oxide and ohmic electrode (OE) metal that provides a high barrier for the generation of oxygen vacancies [defect formation energy (DFE)]. In this work, we present a sophisticated programming algorithm that aims to maximize the endurance within reasonable measurement time. Using this algorithm, we compare ReRAM devices with four different OE metals and confirm the theoretically predicted trend. Thus, our work provides valuable information for device engineering toward higher endurance.

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Chemical Structure of Conductive Filaments in Tantalum Oxide Memristive Devices and Its Implications for the Formation Mechanism

Heisig

Lange

Gutsche

et al. 2022

Adv Elect Materials

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Resistive switching in metal oxides is believed to be caused by a temperature and electric field driven redistribution of oxygen vacancies within a nanometer sized conductive filament. Accordingly, gaining detailed information about the chemical composition of conductive filaments is of key importance for a comprehensive understanding of the switching process. In this work, spectromicroscopy is used to probe the electronic structure of conductive filaments in Ta2O5‐based memristive devices. It is found that resistive switching leads to the formation of a conductive filament with an oxygen vacancy concentration of ≈20%. Spectroscopic insights provide detailed information about the chemical state of the tantalum cations and show that the filament is not composed of a metallic Ta0 phase. As an extreme case, devices after an irreversible dielectric breakdown are investigated. These devices feature larger conductive channels with higher oxygen vacancy concentrations. Using the experimental data as input for finite element simulations, the role of thermodiffusion for the formation process of conductive filaments is revealed. It is demonstrated that thermodiffusion is not the dominating effect for the filament formation here but might play a role in accelerating the forming process, as well as in the stabilization of the filament.

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Study of the SET switching event of VCM-based memories on a picosecond timescale

Cited by 25 publications

References 49 publications

Determining the Electrical Charging Speed Limit of ReRAM Devices

Determining the Electrical Charging Speed Limit of ReRAM Devices

Impact of the Ohmic Electrode on the Endurance of Oxide-Based Resistive Switching Memory

Chemical Structure of Conductive Filaments in Tantalum Oxide Memristive Devices and Its Implications for the Formation Mechanism

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