Breakdown of Al/AlO<sub><i>x</i></sub>/Al Tunneling Junctions

Morozumi, T.; Kaiju, Hideo; Ohtaka, Yuki; Shiiki, Kazuo

doi:10.1143/jjap.43.197

Cited by 5 publications

(6 citation statements)

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“…For the case of the ITO/Al-Nd alloy contact, the FowlerNordheim ͑F-N͒ tunneling phenomenon 19,20 was observed before the breakdown occurred, and the I-V characteristics were nonlinear ͑see Fig. 5a͒.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 5a and b shows the results of the I-V measurements for the ITO/Al-2 atom % Nd alloy and ITO/Al-2 atom % Ni-0.35 atom % La alloy contacts in the Kelvin contact TEGs when the direct rinse with DIW was performed after the photoresist stripping. For the case of the ITO/Al-Nd alloy contact, the Fowler-Nordheim ͑F-N͒ tunneling phenomenon 19,20 was observed before the breakdown occurred, and the I-V characteristics were nonlinear ͑see Fig. 5a͒.…”

Section: Resultsmentioning

confidence: 99%

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Current Path Analysis of the Direct Contact Between ITO and Al–Ni Alloy Films

Kugimiya

Okuno

Kawakami

et al. 2009

J. Electrochem. Soc.

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Al-Ni alloys for single-layer interconnections to be used for amorphous silicon thin-film transistors ͑a-Si TFTs͒ in liquid-crystal displays have been developed. The developed interconnections make possible a direct electrical contact with an indium-tin oxide ͑ITO͒ film without barrier metals, such as Mo and Cr, which are conventionally used for the electrical contacts. In the present paper, we investigated the major current path at the contact between ITO film and the Al-Ni alloy layer using nanoprobes. It was found that the Al 3 Ni precipitations between the ITO film and the Al-Ni alloy layer played an important role of electrically conducting contacts. This led us to a conclusion that it is important to increase local current paths via Al 3 Ni precipitations to achieve a low resistivity at the contact between the ITO film and the Al-Ni alloy layer, which was found to be strongly influenced by the photoresist stripping process successively used for the formation of SiN contact holes in the production of a-Si TFTs.Aluminum ͑Al͒ alloy thin films 1-3 are widely used in the industry of liquid-crystal displays ͑LCDs͒ for gate interconnections of amorphous silicon thin-film transistors ͑a-Si TFTs͒ and source/drain ͑S/D͒ interconnections of low-temperature polycrystalline silicon TFTs. For instance, it is known that aluminum-neodymium ͑Al-Nd͒ alloy films 2,4-6 possess high heat resistance, and the formation of hillock surface defects on the films are suppressed during successive chemical vapor deposition ͑CVD͒ of silicon nitride ͑SiN͒ as well as other high-temperature processes above 300°C in the TFT manufacturing processes. Hence, Al-Nd alloy films are one of the highly reliable materials for interconnections.In the present paper, we propose Al-alloy thin films for direct contacts with indium-tin oxide ͑ITO͒ films and demonstrate that they not only fulfill industrial requirements for the interconnections in LCDs but also can skip unnecessary interconnection fabrication processes, leading to a significant reduction in manufacturing costs. 7 Figure 1a illustrates a conventional stacked layer structure of a-Si TFT gate and S/D interconnections. It is seen that the structure includes refractory metal layers, such as Mo, Cr, and Ti, as diffusion barriers of constituent atoms between the ITO film and the metal interconnections. For this reason, the refractory metals are referred to as barrier metals. 8 Usually, the gate interconnection has a barrier metal layer at the interface with ITO, while the S/D metal interconnection has barrier metal layers on both sides to prevent atomic interdiffusion at the contacts with ITO and a-Si. 9 The barrier metals also achieve low electrical resistivity at the contact with the ITO layer, 9 suppress hillock formation during thermal treatments, 8 and suppress Al diffusion into a-Si in the S/D interconnections. 9,10 Figure 1b illustrates a direct contact structure for gate and S/D interconnections that were studied in the present paper. It is markedly simplified compared with the conventiona...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Current Path Analysis of the Direct Contact Between ITO and Al–Ni Alloy Films

Kugimiya

Okuno

Kawakami

et al. 2009

J. Electrochem. Soc.

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“…It has been reported before that the breakdown voltage of tunnel junctions consisting of dissimilar electrodes is not symmetrical due to the intrinsic electric field caused by the difference in the work function of the electrode materials. [66,67] We also found that our devices were not stable at large positive bias; therefore, we limited the bias window in our experiments to −2.0 to 1.0 V to prevent electrical failure. To ensure that coherent tunneling dominates the charge transport mechanism across the Al-AlO X -Cu junctions, we recorded an I(V) before the optical characterization.…”

Section: Electrical and Optical Characterization Of Tunnel Junctionsmentioning

confidence: 97%

CMOS‐Compatible Electronic–Plasmonic Transducers Based on Plasmonic Tunnel Junctions and Schottky Diodes

Wang

Liu

Hoang

et al. 2021

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plasmonic metals, such as Au and Ag, that are not CMOS compatible. [8] Here, we report an all-electrical, CMOS-compatible electronic-plasmonic transducer based on an Al-AlO X -Cu tunnel junction as the plasmon source, a Si-Cu Schottky diode as the plasmon detector, both connected by a Cu plasmonic strip waveguide. These electronic-plasmonic transducers do not require bulky off-chip components and are useful for future on-chip applications where it is vital to interface plasmonics with microelectronics. [1,9] Often, SPPs are excited by optical means, which requires momentummatching elements such as gratings or prisms. [10] One approach to realize on-chip excitation of SPPs is to miniaturize the light sources where first an electrical signal is converted to photons which then couple to SPPs. [3,11,12] In this context of miniaturization, metalinsulator-metal tunnel junctions (MIM-TJs) are interesting because they can be used as electrically driven plasmon sources where SPPs are directly excited via inelastic tunneling of electrons. [13][14][15] The potential of such plasmonic tunnel junctions has been explored in terms of two-photon emission, [16] above threshold emission (where the emitted photons have higher energy than the applied bias), [17,18] and nonlinear effects [19] have been demonstrated. It is also possible To develop methods to generate, manipulate, and detect plasmonic signals by electrical means with complementary metal-oxide-semiconductor (CMOS)-compatible materials is essential to realize on-chip electronicplasmonic transduction. Here, electrically driven, CMOS-compatible electronic-plasmonic transducers with Al-AlO X -Cu tunnel junctions as the excitation source of surface plasmon polaritons (SPPs) and Si-Cu Schottky diodes as the detector of SPPs, connected via plasmonic strip waveguides of Cu, are demonstrated. Remarkably, the electronic-plasmonic transducers exhibit overall transduction efficiency of 1.85 ± 0.03%, five times higher than previously reported transducers with two tunnel junctions (metal-insulatormetal (MIM)-MIM transducers) where SPPs are detected based on optical rectification. The result establishes a new platform to convert electronic signals to plasmonic signals via electrical means, paving the way toward CMOS-compatible plasmonic components.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202105684.

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“…In addition, tunnel junctions are typically studied under direct-current (DC) conditions which can cause electrical breakdown due to electromigration of metallic atoms and charge accumulation at the metal-oxide interface. [7][8][9] Mostly, electrical circuitry is operated under alternating current (AC) conditions where such issues are mitigated.…”

Section: Introductionmentioning

confidence: 99%

Spatial Control over Stable Light‐Emission from AC‐Driven CMOS‐Compatible Quantum Mechanical Tunnel Junctions

Wang

Hoang

Chu

et al. 2022

Laser & Photonics Reviews

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The potential application of quantum mechanical tunnel junctions as subdiffraction light or surface plasmon sources has been explored for decades, but it has been challenging to create devices with subwavelength spatial control over the light or plasmon excitation. This paper describes spatial control over the electrical excitation of surface‐plasmon polaritons (SPPs) and photons in large‐area junctions of the form of Al–AlOX–Cu complementary metal‐oxide‐semiconductor (CMOS)‐compatible tunnel junctions. Nanoscale spatial control (smallest feature sizes of 150 nm) is achieved by locally fine‐tuning the thickness of the AlOX tunneling barrier resulting in large local tunneling currents and associated SPP excitation rates. Mostly, plasmonic tunnel junctions are studied under DC operation with a relatively large bias (and associated currents) to observe light emission at optical frequencies. Large voltages risk device failure and reduce device lifetimes. Here it is demonstrated that the operational lifetime of AC‐driven plasmonic tunnel junctions is improved by a factor of three. Under DC conditions, slow processes that lead to device failure (e.g., undesirable electromigration leading to shorts) readily occur, thus limiting the device decay time to 9.2 h; but under AC operation, such processes are slow with respect to the voltage changes prolonging the decay time beyond 18.0 h.

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Breakdown of Al/AlO_x/Al Tunneling Junctions

Cited by 5 publications

References 1 publication

Current Path Analysis of the Direct Contact Between ITO and Al–Ni Alloy Films

Current Path Analysis of the Direct Contact Between ITO and Al–Ni Alloy Films

CMOS‐Compatible Electronic–Plasmonic Transducers Based on Plasmonic Tunnel Junctions and Schottky Diodes

Spatial Control over Stable Light‐Emission from AC‐Driven CMOS‐Compatible Quantum Mechanical Tunnel Junctions

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Breakdown of Al/AlOx/Al Tunneling Junctions

Cited by 5 publications

References 1 publication

Current Path Analysis of the Direct Contact Between ITO and Al–Ni Alloy Films

Current Path Analysis of the Direct Contact Between ITO and Al–Ni Alloy Films

CMOS‐Compatible Electronic–Plasmonic Transducers Based on Plasmonic Tunnel Junctions and Schottky Diodes

Spatial Control over Stable Light‐Emission from AC‐Driven CMOS‐Compatible Quantum Mechanical Tunnel Junctions

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Breakdown of Al/AlO_x/Al Tunneling Junctions