Understanding leakage currents through Al2O3 on SrTiO3

Miron, Dror; Krylov, Igor; Baskin, Maria; Yalon, Eilam; Kornblum, Lior

doi:10.1063/1.5119703

Cited by 14 publications

(6 citation statements)

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“…These structures exhibit robust insulating properties, and no hysteresis behavior. [ 32 ] The key difference from the current case is the reduction of the TiO 2 surface, allowing us to pinpoint the interface as the source of vacancies for resistive switching, which are injected (forming) into the Al 2 O 3 layer. [ 13 ] This differs from typical memristors where the resistive switching layer is intentionally enriched with defects, whereas our approach allows the use of an initially low‐defect and insulating Al 2 O 3 , which heralds a memory window of ≈4 orders of magnitude at ±0.2 V. Since the insulating Al 2 O 3 layer is connected in series with the 2DEG (Figure 1a), the LRS resistance can only be explained by modulation of the Al 2 O 3 resistance, to be further discussed on Section 2.3.…”

Section: Resultsmentioning

confidence: 99%

“…The device switches from LRS to HRS. We note that the unconventional use of a highly insulating Al 2 O 3 [ 32 ] is the key here to obtaining the large memory window by increasing the resistance at HRS.…”

Section: Resultsmentioning

confidence: 99%

“…TMA and H 2 O are used as the Al and the oxygen precursors, respectively. The Al 2 O 3 deposition sequence [ 32 ] consists of TMA injection (0.1 s)/purge (10 s)/H 2 O (0.3 s)/purge (5 s). Pt top electrodes (50 nm thick) are deposited on top of the Al 2 O 3 layer through a shadow mask with a diameter of 120 µm using e‐beam deposition.…”

Section: Methodsmentioning

confidence: 99%

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Scalable Al₂O₃–TiO₂ Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices

Wang

Zhang

et al. 2022

Adv Elect Materials

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Resistive switching devices herald a transformative technology for memory and computation, offering considerable advantages in performance and energy efficiency. Here, a simple and scalable material system of conductive oxide interfaces is employed, and their unique properties are leveraged for a new type of resistive switching device. An Al2O3–TiO2‐based valence‐change resistive switching device, where the conductive oxide interface serves both as the bottom electrode and as a reservoir of defects for switching, is demonstrated. The amorphous–polycrystalline Al2O3–TiO2 conductive interface is obtained following the technological path of simplifying the fabrication of the 2D electron gases (2DEGs), making them scalable for practical mass integration. Physical analysis of the device chemistry and microstructure with comprehensive electrical analysis of its switching behavior and performance is combined. The origin of the resistive switching is pinpointed to the conductive oxide interface, which serves both as the bottom electrode and as a reservoir of oxygen vacancies. The latter plays a key role in valence‐change resistive switching devices. The new device, based on scalable and complementary metal–oxide–semiconductor (CMOS)‐technology‐compatible fabrication processes, opens new design spaces toward increased tunability and simplification of the device selection challenge.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Scalable Al₂O₃–TiO₂ Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices

Wang

Zhang

et al. 2022

Adv Elect Materials

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“…The oxygen vacancies driven from the interface into the insulating oxide under high electric fields are the key in enabling the resistive switching behavior. A key feature of this work is the application of low-defect Al 2 O 3 [89], where the 2DEG serves as the bottom electrode and as the source of oxygen vacancies. The oxygen vacancies are injected by the electric field into the insulating Al 2 O 3 to form the conductive filament.…”

Section: Two-dimensional Electron Gases At Oxide Interfaces For Resistive Random-access Memory Applicationsmentioning

confidence: 99%

“…The oxygen vacancies are injected by the electric field into the insulating Al 2 O 3 to form the conductive filament. The practical consequence of this approach is the trigger of resistive switching behavior as compared to the Pt/Al 2 O 3 /Nb:SrTiO 3 stuctured device [89] and a large OFF/ON resistance ratio afforded by using a good insulator of Al 2 O 3 as the resistive switching layer and the 2DEG as the bottom electrode [24,90,91]. The key shortcoming here was the large set/reset voltages, on the order of ±7 V, another consequence of the insulating Al 2 O 3 .…”

Section: Two-dimensional Electron Gases At Oxide Interfaces For Resistive Random-access Memory Applicationsmentioning

confidence: 99%

Harnessing Conductive Oxide Interfaces for Resistive Random-Access Memories

Kvatinsky

Kornblum

2021

Front. Phys.

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Two-dimensional electron gases (2DEGs) can be formed at some oxide interfaces, providing a fertile ground for creating extraordinary physical properties. These properties can be exploited in various novel electronic devices such as transistors, gas sensors, and spintronic devices. Recently several works have demonstrated the application of 2DEGs for resistive random-access memories (RRAMs). We briefly review the basics of oxide 2DEGs, emphasizing scalability and maturity and describing a recent trend of progression from epitaxial oxide interfaces (such as LaAlO3/SrTiO3) to simple and highly scalable amorphous-polycrystalline systems (e.g., Al2O3/TiO2). We critically describe and compare recent RRAM devices based on these systems and highlight the possible advantages and potential of 2DEGs systems for RRAM applications. We consider the immediate challenges to revolve around scaling from one device to large arrays, where further progress with series resistance reduction and fabrication techniques needs to be made. We conclude by laying out some of the opportunities presented by 2DEGs based RRAM, including increased tunability and design flexibility, which could, in turn, provide advantages for multi-level capabilities.

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Low Leakage in High‐k Perovskite Gate Oxide SrHfO₃

Kim

Song

Yun

et al. 2023

Adv Elect Materials

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of high-k gate oxide. The power consumption of the device can be categorized by two distinct origins, which are static and dynamic power consumption. [1] As the geometries of the devices are getting smaller, the static power consumption begins to dominate, which is intimately correlated with the leakage current in the devices. [1][2][3][4] Furthermore, the leakage current in off-state is important for device reliability as the on-state currents shrink along with scaling down of the device size. Since the high-k dielectric is needed to overcome the leakage current issue of silicon oxides, [5][6][7] the requirements for the ideal high-k materials are large dielectric constant, low leakage current, and large breakdown field. Especially, in order for the high-k dielectric to carry low leakage current, large bandgap (>5 eV), large conduction band offset (CB offset > 1 eV), and low density of the defect states inside the bandgap which may create a conduction path are necessary conditions. [8,9] In this direction binary oxides with large bandgaps such as Y 2 O 3 and Al 2 O 3 were investigated. [5] However, their dielectric constants have not been sufficiently high. Binary oxides such as TiO 2 and Ta 2 O 5 are high-k material but they were found to be not stable on silicon. [5] Other binary oxides such as HfO 2 , ZrO 2 , and La 2 O 3 are suitable high-k materials on silicon and commercial products using those materials are already in the semiconductor market for central processing unit, dynamic random access Reducing the leakage current through the gate oxide is becoming increasingly important for power consumption reduction as well as reliability in integrated circuits as the semiconducting devices continue to scale down. Here, this work reports on the high-k dielectric SrHfO 3 (SHO) based devices with ultralow leakage current density via pulsed laser deposition (PLD). The ultralow current density is achieved by optimizing the growth conditions and the associated structural properties. In the optimized conditions, the dielectric properties of the 50-nm-thick SHO capacitors are measured: high dielectric constant (κ = 32), low leakage current density (<10 −8 A cm −2 at 2 MV cm −1 ), and large breakdown field (E BD > 4 MV cm −1 ). The surprisingly low leakage current density of SHO is ascribed to the large bandgap (≈6 eV), the large conduction band offset (CB offset > 3 eV) with respect to the semiconductor, and the low density of defect states inside the bandgap. The optimized SHO dielectric with high dielectric constant and ultralow leakage current density is proposed for future low-power consumption devices based on Si as well as perovskite oxide semiconductors.

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Understanding leakage currents through Al2O3 on SrTiO3

Cited by 14 publications

References 54 publications

Scalable Al₂O₃–TiO₂ Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices

Scalable Al₂O₃–TiO₂ Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices

Harnessing Conductive Oxide Interfaces for Resistive Random-Access Memories

Low Leakage in High‐k Perovskite Gate Oxide SrHfO₃

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Understanding leakage currents through Al2O3 on SrTiO3

Cited by 14 publications

References 54 publications

Scalable Al2O3–TiO2 Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices

Scalable Al2O3–TiO2 Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices

Harnessing Conductive Oxide Interfaces for Resistive Random-Access Memories

Low Leakage in High‐k Perovskite Gate Oxide SrHfO3

Contact Info

Product

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Scalable Al₂O₃–TiO₂ Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices

Scalable Al₂O₃–TiO₂ Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices

Low Leakage in High‐k Perovskite Gate Oxide SrHfO₃