Sputtering and nitridation of transition metal surfaces under low energy, steady state nitrogen ion bombardment

Phadke, Parikshit; Kruijs, R. W. E. van de; Bijkerk, F.

doi:10.1016/j.apsusc.2019.144529

Cited by 17 publications

(20 citation statements)

References 42 publications

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“…The peaks at 399 and 401.3 eV correspond to N atoms of hexadecylamine and hexadecylammonium ions, respectively . The peak at low energy corresponds to N atoms adsorbed on the surface of the Ru NPs and/or to a surface nitridation of the Ru NPs . It shows a partial decomposition of the HDA, resulting from the C–N activation, likely catalyzed by the Ru nanoparticles in the presence of molecular hydrogen.…”

Section: Resultsmentioning

confidence: 98%

Ruthenium Icosahedra and Ultrathin Platelets: The Role of Surface Chemistry on the Nanoparticle Structure

et al. 2022

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The control of the crystalline structure and shape (crystal habit) of nanoparticles (NPs) is the key to controlling their physical and chemical properties. Among the different metals, the crystallogenesis of ruthenium NPs has been less studied, and until recently, the Ru NP crystal structure and morphology have been considered as presenting less versatility than the face-centered cubic (fcc) metals of the platinum group. Here, we show that while the hydrogenation of [Ru(COD)(COT)] in solutions containing a long-chain amine (hexadecylamine, HDA) in large excess leads to isotropic NPs adopting the expected hexagonal close-packed (hcp) structure of bulk Ru, a long-chain carboxylic acid (lauric acid, LA) in large excess induces the formation of Ru nano-objects of two original structures: ultrathin platelets and icosahedra. The latter have never been produced so systematically by other methods. We show that carbon monoxide, produced in situ by the decarbonylation of lauric acid, plays a pivotal role in the stabilization of the Ru icosahedra. This result is supported by density functional theory (DFT) calculations, which show that above a critical surface coverage of CO, small Ru icosahedra are more stable than the Ru bipyramid polyhedra crystallizing in the hcp structure. Thus, in situ production of CO results in a competition between icosahedral and hcp seeds, which explains the mixture of icosahedra and ultrathin platelets. Another effect of the large excess of lauric acid is the stabilization of the ruthenium precursors in solution, limiting the nucleation extent and slowing down the NP growth. While the growth of the icosahedral seeds is limited because of the structural strains, the growth of the hcp seeds preferentially develops the (0001) facets, leading to ultrathin platelets and threefold stars.

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Section: Resultsmentioning

confidence: 98%

Ruthenium Icosahedra and Ultrathin Platelets: The Role of Surface Chemistry on the Nanoparticle Structure

et al. 2022

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“…Still, care should be taken regarding gas purity since the heavier ions may have significantly more impact on materials at the same ion energy, and both oxygen and nitrogen compounds may be chemically active. 61,62 Also, hydrocarbons and volatile hydrides may have a significant impact already at trace levels since these may be decomposed by the EUV to result in deposition of carbonaceous layers on mirrors 63 and reticles. 64…”

Section: Gas Puritymentioning

confidence: 99%

EUV-induced hydrogen plasma: pulsed mode operation and confinement in scanner

Kerkhof

Yakunin

Astakhov

et al. 2021

J. Micro/Nanopattern. Mats. Metro.

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In recent years, EUV lithography scanner systems have entered high-volume manufacturing for state-of-the-art integrated circuits, with critical dimensions down to 10 nm. This technology uses 13.5-nm EUV radiation, which is shaped and transmitted through a near-vacuum H 2 background gas. This gas is excited into a low-density H 2 plasma by the EUV radiation, as generated in pulsed mode operation by the laser-produced plasma in the EUV source. Thus, in the confinement created by the walls and mirrors within the scanner system, a reductive plasma environment is created that must be understood in detail to maximize mirror transmission over the lifetime and to minimize molecular and particle contamination in the scanner. In addition to the irradiated mirrors, reticle, and wafer, the plasma and radical load to the surrounding construction materials also must be considered. We provide an overview of the EUV-induced plasma in the scanner context. Special attention is given to the plasma parameters in a confined geometry, such as that found in the scanner area near the reticle. It is shown that plasma confinement and resulting contributions from secondary electron emission delay the formation of the plasma sheath and thereby reduce the peak ion energies to below the sputtering threshold for mirrors and construction materials. Furthermore, for a confined pulsed plasma with a pulse period shorter than the decay time of the plasma, the plasma consists of a quasi-steady-state cold background plasma and periodic transient peaks in ion energy and ion flux. In terms of modeling, this means that no assumptions can be made on the electron distribution functions and a (Monte-Carlo) particle-in-cell (PIC) model is needed. We present an extension of the PIC model approach to complex three-dimensional geometries and to multiple pulses using a hybrid PIC-diffusion approach. Also, the translation of these specific plasma parameters to off-line setups and the aspects that must be included to make a meaningful translation from off-line laboratory EUV setups to the scanner plasma are discussed. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…Charged particle-surface interactions as an important field have been intensively researched over several decades. Most studies have focused on, for instance, ion- or electron-induced sputtering and desorption, 1 ion stimulated surface electron emission, 2–4 energy loss, 5 and ion induced surface nanostructures. 6–9 The charge state in scattered beams after projectile scattering from an insulator ionic-crystal surface has received much attention.…”

Section: Introductionmentioning

confidence: 99%

Negative ion formation by neutral hydrogen atom grazing scattering from a LiF(100) surface

et al. 2021

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Sputtering and nitridation of transition metal surfaces under low energy, steady state nitrogen ion bombardment

Cited by 17 publications

References 42 publications

Ruthenium Icosahedra and Ultrathin Platelets: The Role of Surface Chemistry on the Nanoparticle Structure

Ruthenium Icosahedra and Ultrathin Platelets: The Role of Surface Chemistry on the Nanoparticle Structure

EUV-induced hydrogen plasma: pulsed mode operation and confinement in scanner

Negative ion formation by neutral hydrogen atom grazing scattering from a LiF(100) surface

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