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1. Surface treatment of TaN for sub-2 nm, smooth, and conducting atomic layer deposition Ru films

   https://doi.org/10.1116/6.0003440  

   Feit, Corbin; Kumar, Udit; Islam, Md Rafiqul; Tomar, Luis; Berriel, S Novia; Gaskins, John T; Hopkins, Patrick E; Seal, Sudipta; Banerjee, Parag (May 2024, Journal of Vacuum Science & Technology A)

   Atomic layer deposition (ALD) of ruthenium (Ru) is being investigated for next generation interconnects and conducting liners for copper metallization. However, integration of ALD Ru with diffusion barrier refractory metal nitrides, such as tantalum nitride (TaN), continues to be a challenge due to its slow nucleation rates. Here, we demonstrate that an ultraviolet-ozone (UV-O3) pretreatment of TaN leads to an oxidized surface that favorably alters the deposition characteristics of ALD Ru from islandlike to layer-by-layer growth. The film morphology and properties are evaluated via spectroscopic ellipsometry, atomic force microscopy, electrical sheet resistance measurements, and thermoreflectance. We report a 1.83 nm continuous Ru film with a roughness of 0.19 nm and a sheet resistance of 10.8 KΩ/□. The interface chemistry between TaN and Ru is studied by x-ray photoelectron spectroscopy. It is shown that UV-O3 pretreatment, while oxidizing TaN, enhances Ru film nucleation and limits further oxidation of the underlying TaN during ALD. An oxygen “gettering” mechanism by TaN is proposed to explain reduced oxygen content in the Ru film and higher electrical conductivity compared to Ru deposited on native-TaN. This work provides a simple and effective approach using UV-O3 pretreatment for obtaining sub-2 nm, smooth, and conducting Ru films on TaN surfaces. 

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2. High‐Pressure Synthesis and Thermal Conductivity of Semimetallic θ‐Tantalum Nitride

   https://doi.org/10.1002/adfm.202212957  

   Lee, Hwijong; Zhou, Yuanyuan; Jung, Sungyeb; Li, Hongze; Cheng, Zhe; He, Jiaming; Chen, Jie; Sokalski, Peter; Dolocan, Andrei; Gearba‐Dolocan, Raluca; et al (February 2023, Advanced Functional Materials)

   Abstract The lattice thermal conductivity (κ_ph) of metals and semimetals is limited by phonon‐phonon scattering at high temperatures and by electron‐phonon scattering at low temperatures or in some systems with weak phonon‐phonon scattering. Following the demonstration of a phonon band engineering approach to achieve an unusually high κ_phin semiconducting cubic‐boron arsenide (c‐BAs), recent theories have predicted ultrahigh κ_phof the semimetal tantalum nitride in the θ‐phase (θ‐TaN) with hexagonal tungsten carbide (WC) structure due to the combination of a small electron density of states near the Fermi level and a large phonon band gap, which suppress electron‐phonon and three‐phonon scattering, respectively. Here, measurements on the thermal and electrical transport properties of polycrystalline θ‐TaN converted from the ε phase via high‐pressure synthesis are reported. The measured thermal conductivity of the θ‐TaN samples shows weak temperature dependence above 200 K and reaches up to 90 Wm⁻¹K⁻¹, one order of magnitude higher than values reported for polycrystalline ε‐TaN and δ‐TaN thin films. These results agree with theoretical calculations that account for phonon scattering by 100 nm‐level grains and suggest κ_phincrease above the 249 Wm⁻¹K⁻¹value predicted for single‐crystal WC when the grain size of θ‐TaN is increased above 400 nm. 

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3. RRAM Devices with Plasma Treated HfO2 with Ru as Top Electrode for In-Memory Computing Hardware

   https://doi.org/10.1149/MA2021-0212615mtgabs  

   Patel, Y.D.; Misra, D; Triyoso, D.H.; Tapily, K.; Clark, R.D.; Consiglio, S.; Pattanaik, G.; Cole, C.; Raley, A.; Wajda, C.S.; et al (January 2021, ECS transactions)

   This work investigates the role of extra oxygen vacancies, introduced by a hydrogen plasma at midpoint of deposition of a 6 nm thick HfO2 to reduce the switching power consumption in a RRAM device. Initially TiN, which is a commonly used metal in CMOS technology, was used as the top electrode for treated HfO2. Subsequently Ru and TaN as top electrodes were explored to enhance the switching behavior and power consumption. A range of compliance currents from 1 nA to 1 µA were used to evaluate the switching characteristics. The role of both TaN and Ru as bottom metal was also evaluated. With Ru as top metal the device switched at a compliance current of 1 nA and higher. Whereas when Ru was used as bottom electrode, devices were unable to switch below a compliance current of 50 µA. For TaN as top metal electrode, devices switched at and above 1 µA CC whereas with TaN as bottom metal the initial switching was at CC of 2 µA. It was observed that use of Ru as a top metal significantly reduced the switching energy of the plasma treated HfO2 RRAM device but was ineffective when used as a bottom metal. 

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4. Learning 2D Temporal Adjacent Networks for Moment Localization with Natural Language

   Zhang, S; Peng, H; Fu, J; Luo, J. (February 2020, Proceedings of the AAAI Conference on Artificial Intelligence)

   We address the problem of retrieving a specific moment from an untrimmed video by a query sentence. This is a challenging problem because a target moment may take place in relations to other temporal moments in the untrimmed video. Existing methods cannot tackle this challenge well since they consider temporal moments individually and neglect the temporal dependencies. In this paper, we model the temporal relations between video moments by a two-dimensional map, where one dimension indicates the starting time of a moment and the other indicates the end time. This 2D temporal map can cover diverse video moments with different lengths, while representing their adjacent relations. Based on the 2D map, we propose a Temporal Adjacent Network (2D-TAN), a single-shot framework for moment localization. It is capable of encoding the adjacent temporal relation, while learning discriminative features for matching video moments with referring expressions. We evaluate the proposed 2D-TAN on three challenging benchmarks, i.e., Charades-STA, ActivityNet Captions, and TACoS, where our 2D-TAN outperforms the state-of-the-art. 

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5. Linking marine core lithofacies and mineral and grain-size compositions on the Baffin Island margin: changes in provenance and transport

   https://doi.org/10.2110/jsr.2020.50  

   Andrews, J.T.; Jenner, K.; Campbell, C. (January 2020, Journal of sedimentary research)

   We evaluate the linkages between lithofacies and mineral composition of late Quaternary sediments along the Baffin Slope for cores 2013029 64, 74, and 77. Four major lithofacies were identified: diamicton (L1), laminated red-brown mud (L2), tan carbonate mud (L3), and brown bioturbated mud (L4). In addition, goldbrown mud (L2a) beds were identified within red-brown mud throughout the Baffin margin and a thin, locally distributed light gray mud (L2b), also identified within red-brown mud, was localized to the Home Bay region. A classification decision tree (CDT) correctly predicted ~ 87% of the lithofacies based on five binary choices based on the estimated weight %s of (in order): quartz, kaolinite, plagioclase, iron oxides, and smectites. The detrital tan carbonate (DC) minerals, calcite and dolomite, did not appear in the chosen CDT solution although this lithofacies is easily recognized in cores because of its tan color and the facies is well predicted in the CDT. The addition of grain size did not substantially improve the prediction of the lithofacies although it did change the % importance of the minerals in the CDT. 

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