Full ALD Ta 2 O 5 -based stacks for resistive random access memory grown with in vacuo XPS monitoring

Egorov, Konstantin; Lebedinskiǐ, Yu. Yu.; Markeev, Andrey M.; Орлов, О. М.

doi:10.1016/j.apsusc.2015.07.217

Cited by 40 publications

(16 citation statements)

References 28 publications

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“…Figure 1 a–c shows the XPS spectra of Ta 4f, Al 2p, and Ti 2p, respectively. Ta 4f 7/2 and Ta 4f 5/2 peaks were centered at 26.3 eV and 28.2 eV, respectively, at the surface (0 s) [ 34 ]. Subsequently, the suboxide was detected after 5 s because of the Ta-O-Al bond near the Ta 2 O 5 /Al 2 O 3 interface [ 35 ].…”

Section: Resultsmentioning

confidence: 99%

Improved Intrinsic Nonlinear Characteristics of Ta2O5/Al2O3-Based Resistive Random-Access Memory for High-Density Memory Applications

Ryu

Kim

2020

Materials

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The major hindrance for high-density application of two-terminal resistive random-access memory (RRAM) array design is unintentional sneak path leakage through adjacent cells. Herein, we propose a bilayer structure of Ta2O5/Al2O3-based bipolar type RRAM by evaluating the intrinsic nonlinear characteristics without integration with an additional transistor and selector device. We conducted X-ray photoelectron spectroscopy (XPS) analysis with different etching times to verify Ta2O5/Al2O3 layers deposited on the TiN bottom electrode. The optimized nonlinear properties with current suppression are obtained by varying Al2O3 thickness. The maximum nonlinearity (~71) is achieved in a Ta2O5/Al2O3 (3 nm) sample. Furthermore, we estimated the comparative read margin based on the I-V characteristics with different thicknesses of Al2O3 film for the crossbar array applications. We expect that this study about the effect of the Al2O3 tunnel barrier thickness on Ta2O5-based memristors could provide a guideline for developing a selector-less RRAM application.

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Section: Resultsmentioning

confidence: 99%

Improved Intrinsic Nonlinear Characteristics of Ta2O5/Al2O3-Based Resistive Random-Access Memory for High-Density Memory Applications

Ryu

Kim

2020

Materials

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“…Any particular niobate or tantalate can be characterized by a set of binding energies (BE) related to maximums of Nb 3d or Ta 4f and O 1s lines. However, a significant scattering exists in binding energy values reported in the literature Nb 3d 3/2 (210 eV) and Nb 3d 5/2 (207 eV) or Ta 4f 5/2 (28 eV) and Ta 4f 7/2 (26 eV) components even for such stable compounds as Nb 2 O 5 or Ta 2 O 5 . The binding energy differences Δ(O―Nb) = B E (O 1s) − B E (Nb 3d 5/2 ) and Δ(O―Ta) = B E (O 1s) − B E (Ta 4f 7/2 ) are suitable parameters to characterize average Nb―O bonding in niobates (322.2‐323.6 eV) and Ta―O bonding in tantalates (502.7‐504.4 eV) …”

Section: Introductionmentioning

confidence: 97%

X‐ray photoelectron spectroscopy study of neodymium niobate and tantalate precursors and thin films

Bruncková

Kolev

Kaňuchová

2018

Surface & Interface Analysis

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Neodymium niobate NdNbO4 (NNO) and tantalate NdTaO4 (NTO) thin films (~100 nm) were prepared by sol‐gel/spin‐coating process on Al2O3 substrate with LaNbO4/PbZrO3 interlayer and annealing at 1000°C. Surface chemistry was investigated by X‐ray photoelectron spectroscopy (XPS). The core‐level XPS studies of sol‐gel NNO and NTO were performed for the first time. The binding energy differences Δ(O―Nb) and Δ(O―Ta) were used to characterize average energies of Nb―O bonding in NNO (322.9 eV) and Ta―O bonding in NTO (504.2 eV). The XPS demonstrated single valence state of Nd (Nd3+) in precursors. Nd concentration (at. %) decreases from 22% in precursors to 7% in films considering the substrate contains C, Al, Si, Pb, and Zr elements (37%) at Nb or Ta (5%) and O (51%). The X‐ray diffraction analyses verified formation of the monoclinic (M‐NdNbO4 or M′‐NdTaO4), orthorhombic (O‐NdNbO4) and tetragonal (T‐NdTaO4) phases in precursors and films. Single valence state of Nd3+ was confirmed in these films designed for the application in environmental electrolytic thin film devices.

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“…Filamentary RS normally implies the necessity of an electroforming step for the RS initiation. [1][2][3][4][5] However, the process of filament formation is believed to be stochastic in nature, which leads to variations in the switching parameters. Even when the forming process can be appropriately performed in the discrete RS cells, the CBA structure experience the uncontrollable formation of the conductive filaments, which significantly reduces the array level uniformity and reliability.…”

Section: Introductionmentioning

confidence: 99%

Resistance Switching Peculiarities in Nonfilamentary Self‐Rectified TiN/Ta₂O₅/Ta and TiN/HfO₂/Ta₂O₅/Ta Stacks

Kuzmichev

Chernikova

Kozodaev

et al. 2020

Physica Status Solidi (a)

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Herein, Ta2O5/Ta interface‐based TiN/Ta2O5/Ta and TiN/HfO2/Ta2O5/Ta resistance switched (RS) stacks are investigated. The stacks reveal area‐dependent RS behavior indicating nonfilamentary (homogeneous) current transport. The nonfilamentary nature of the stacks provides high reproducibility of current–voltage hysteresis loops and the absence of electroforming. It is demonstrated that the nature of the current hysteresis in single Ta2O5‐based stacks obeys space‐charge‐limited conduction, and the space charge responsible for this behavior is formed by filled/emptied traps at the Ta/Ta2O5 interface. Due to the high potential barrier at the TiN/HfO2 interface, as measured using X‐ray photoelectron spectroscopy, sufficiently thick HfO2 (≈4 nm) blocks the trapping/detrapping process, thereby reducing the current hysteresis. The evaluated current mechanism results in a high rectification ratio of the TiN/Ta2O5/Ta device of ≈1.6 × 104. However, relatively short retention is inherent to the observed switching mechanism.

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Full ALD Ta 2 O 5 -based stacks for resistive random access memory grown with in vacuo XPS monitoring

Cited by 40 publications

References 28 publications

Improved Intrinsic Nonlinear Characteristics of Ta2O5/Al2O3-Based Resistive Random-Access Memory for High-Density Memory Applications

Improved Intrinsic Nonlinear Characteristics of Ta2O5/Al2O3-Based Resistive Random-Access Memory for High-Density Memory Applications

X‐ray photoelectron spectroscopy study of neodymium niobate and tantalate precursors and thin films

Resistance Switching Peculiarities in Nonfilamentary Self‐Rectified TiN/Ta₂O₅/Ta and TiN/HfO₂/Ta₂O₅/Ta Stacks

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Full ALD Ta 2 O 5 -based stacks for resistive random access memory grown with in vacuo XPS monitoring

Cited by 40 publications

References 28 publications

Improved Intrinsic Nonlinear Characteristics of Ta2O5/Al2O3-Based Resistive Random-Access Memory for High-Density Memory Applications

Improved Intrinsic Nonlinear Characteristics of Ta2O5/Al2O3-Based Resistive Random-Access Memory for High-Density Memory Applications

X‐ray photoelectron spectroscopy study of neodymium niobate and tantalate precursors and thin films

Resistance Switching Peculiarities in Nonfilamentary Self‐Rectified TiN/Ta2O5/Ta and TiN/HfO2/Ta2O5/Ta Stacks

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Resistance Switching Peculiarities in Nonfilamentary Self‐Rectified TiN/Ta₂O₅/Ta and TiN/HfO₂/Ta₂O₅/Ta Stacks