Atomic-scale effects of sub-keV ions during growth and subsequent ion-beam analysis of molybdenum thin films

Klaver, Peter; Haddeman, Edwin F. C.; Thijsse, Barend J.

doi:10.1016/s0168-583x(99)00050-6

Cited by 17 publications

(8 citation statements)

References 8 publications

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“…The binding energy between a gas atom and a vacancy is very high. For example, the binding energy of a hydrogen-vacancy pair is 1.07 eV in molybdenum and 1.16 eV in tungsten, 3) while that of a helium-vacancy pair is 3.1 eV 4) in molybdenum and 4.15 eV in tungsten. 5) Thus, hydrogen or helium is trapped by vacancies to form high-density hydrogen or helium bubbles at low temperature.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Simulation of Multiplier Effects of Helium Plasma and Neutron Irradiation on Microstructural Evolution in Tungsten

Yoshida

Yoshiie

2005

Mater. Trans.

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Plasma-facing and high heat flux materials in a fusion reactor suffer two types of damage: displacement damage caused mainly by highenergy neutrons and surface damage, such as erosion, sputtering, and blistering, caused by hydrogen and helium plasma. Usually, these two kinds of damage are investigated separately. In the present study, multiplier effects of helium plasma and neutron irradiation on microstructural evolution in tungsten were investigated using computer simulations based on a rate theory. Neutron irradiation with 10 À6 dpaÁs À1 at 873 K and a helium flux of 10 18 m À2 Ás À1 with 10-keV energy were used as typical irradiation conditions. The effects of irradiation temperature and defect production rate on the interaction between helium and defects were also investigated. The simulation results revealed the rapid diffusion of helium in tungsten. The helium concentration was saturated in tungsten 0.067 mm thick within 0.01 s at 873 K, and the formation of heliumvacancy clusters was nearly uniform in the matrix except at the surfaces facing towards and away from the irradiation after 0.01 s. This meant that the 10-keV helium plasma could enhance formation of helium-vacancy clusters in the region without damage produced by helium. The concentration of 6He-V clusters reached a very high level (10 À6 ) even after a 1-s irradiation with a defect production rate of 10 À6 dpaÁs À1 at 873 K. The concentration of helium-vacancy clusters decreased with increasing irradiation temperature and decreasing defect production rate. The accumulation of helium and the formation of helium-vacancy clusters depended on not only the vacancy concentration, which was determined by the irradiation temperature and defect production rate, and helium concentrations, but also irradiation time.

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Section: Introductionmentioning

confidence: 99%

Dynamic Simulation of Multiplier Effects of Helium Plasma and Neutron Irradiation on Microstructural Evolution in Tungsten

Yoshida

Yoshiie

2005

Mater. Trans.

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“…Although most published MD simulations of energetic deposition of metals have been for fcc metals, due to the availability of EAM potentials for these materials, some similar calculations have been published for body centered cubic (bcc) metals. Robbemond and Thijsse [45] and Klaver, Haddeman, and Thijsse [46] have studied IBAD of Mo with 100-eV Ar bombardment. They determined that (110) films were much rougher than (100) films, and that these rougher films could be considerably smoothed by the Ar-ion assist.…”

Section: Simulation Of Energetic Thin Film Deposition With Metal Atommentioning

confidence: 99%

Molecular Dynamics Simulation of Thin Film Growth with Energetic Atoms

Gilmore

Sprague²

2002

Chemical Physics of Thin Film Deposition Processes for Micro- And Nano-Technologies

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Thin Film Deposition With Energetic AtomsHyperthermal atoms are deposited upon a substrate in thin film deposition processes. Even when the atoms in the vapor phase are not intentionally accelerated to the substrate, the vapor phase atoms are attracted to the substrate surface with a potential of a few electron volts (eV) because of the interaction between the incoming atom and the substrate. Some deposition processes such as ion beam assisted deposition(IBAD), ion beam deposition (IBD), sputter deposition(S), and plasma enhanced chemical vapor deposition (PECVD)result in ions striking the substrate with energies from 10 to over 100 eV as shown in figure 1[1].Research has demonstrated that energetic incident atoms can increase the density [2], modify the microstructure [3], chemistry [4], and stress [5] ofthin films. Several examples where energetic deposition techniques are known to affect the physical properties are in the deposition of multilayered metals and in the low temperature epitaxial growth of Si. Multilayered metals such as CrfFe and Co/Cu have a giant magnetoresistance (GMR) effect that is a result of changes in scattering of electrons from interfaces as a magnetic field is applied to the multilayer [6,7]. Fullerton and coworkers have shown that the condition and character of the interface is critical to the GMR effect [8], and that the character of the interface can be modified by utilizing energetic incident atoms. In semiconductor systems it is desired to grow epitaxial Si at low temperatures where diffusion will not significantly mix the layers of doped semiconductors, insulators or metals that have previously been created. It has been observed that if energetic Si atoms are deposited at 400°C rather than thermal energy 283 Y. Pauleau (ed.), Chemical Physics of Thin Film Deposition Processes for

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“…As a result, swelling and embrittlement of the materials can occur by the accumulation of hydrogen and helium [1][2][3]. Reported works indicate that hydrogen/helium atoms could interact with irradiation-induced vacancy defects, and they could also migrate and aggregate to form (H/He)-V clusters or bubbles, which might cause undesired changes in the material properties [4,5].…”

Section: Introductionmentioning

confidence: 99%

Positron Annihilation Spectroscopy Characterization of Formation of Helium/Hydrogen-Vacancy Nano-Clusters in FeCr Alloy

et al. 2020

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In the present work, Fe9Cr model alloy was implanted with 100 keV He and 60 keV H ions at room temperature. Positron annihilation Doppler broadening spectroscopy was employed to detect (H, He)-V complexes with open volume in the irradiated specimens. The results show that the positron is sensitive to the relative position of the gas atoms decorating the open volume; i.e., to the configuration of the (H, He)-V complexes. The formation of H-vacancy clusters after H implantation and a large number of vacancies can be retained after H-V decomposes at room temperature. For the pre-implanted He situation (He + H), He-vacancy clusters are formed in advance and the post-implanted H introduces a large number of vacancies and decomposable H-vacancy clusters. The He-vacancy clusters forming in advance may recombine with vacancies and H atoms to form stable He-vacancy clusters and a small amount of He-H-V complex.

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Atomic-scale effects of sub-keV ions during growth and subsequent ion-beam analysis of molybdenum thin films

Cited by 17 publications

References 8 publications

Dynamic Simulation of Multiplier Effects of Helium Plasma and Neutron Irradiation on Microstructural Evolution in Tungsten

Dynamic Simulation of Multiplier Effects of Helium Plasma and Neutron Irradiation on Microstructural Evolution in Tungsten

Molecular Dynamics Simulation of Thin Film Growth with Energetic Atoms

Positron Annihilation Spectroscopy Characterization of Formation of Helium/Hydrogen-Vacancy Nano-Clusters in FeCr Alloy

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