Anisotropy effects in physical sputtering investigated by laser-induced fluorescence spectroscopy

Goehlich, A.; Niemöller, N.; Döbele, H. F.

doi:10.1103/physrevb.62.9349

Cited by 50 publications

(42 citation statements)

References 21 publications

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“…The shapes of these distributions are only weakly dependent on the positive ion energy, at least for energies varying by a few tens of volts, as we already observed experimentally in [59], and had already been observed previously 76,77 . However, the energy of the impinging positive ion is primordial to reproduce correctly the maximum energy of the backscattered IDFs (see Figure 3).…”

Section: Iii) Idf Versus Positive Ion Energysupporting

confidence: 86%

Production of negative ions on graphite surface in H2/D2 plasmas: Experiments and srim calculations

et al. 2012

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In previous works, surface-produced negative-ion distribution-functions have been measured in H 2 and D 2 plasmas using graphite surfaces (HOPG). In the present paper we use the SRIM software to interpret the measured negative-ion distribution-functions. For this purpose the distribution-functions of backscattered and sputtered atoms arising due to the impact of hydrogen ions on a-CH and a-CD surfaces are calculated. The SRIM calculations confirm the experimental deduction that backscattering and sputtering are the mechanisms of the origin of the creation of negative ions at the surface. It is shown that the SRIM calculations compare well with the experiments regarding the maximum energy of the negative ions and reproduce the experimentally observed isotopic effect. A discrepancy between calculations and measurements is found concerning the yields for backscattering and sputtering. An explanation is proposed based on a study of the emitted-particle angulardistributions as calculated by SRIM. A-IntroductionThe ITER project and its successor DEMO (first nuclear-fusion based power plant prototype) aim at demonstrating power production by magnetic confinement nuclear fusion. Plasma start-up and continuous operation in the case of a tokamak reactor require very efficient heating and non-inductive current drive systems. Neutral beam injection (NBI) which uses high power beams of fast neutral atoms of hydrogen isotopes to heat the plasma is a promising candidate. In most existing NBI systems on contemporary fusion experiments a beam of positive ions is extracted from a conventional ion source, accelerated to energies of the order of 100 keV and neutralized via charge exchange in a background of neutral hydrogen. Due to the much larger physical dimensions the NBI systems for both ITER and DEMO require neutral beam energies in the 1 to 2 MeV range where the neutralization of positive ions becomes very inefficient and only the negative ions can be neutralized with sufficient yield. Hence the development of high current negative ion sources (50A D-beam for ITER) is crucial to the development of the ITER and DEMO NBI systems. The highcurrent-density negative-ion source for ITER 1 is currently the subject of intense research

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Section: Iii) Idf Versus Positive Ion Energysupporting

confidence: 86%

Production of negative ions on graphite surface in H2/D2 plasmas: Experiments and srim calculations

et al. 2012

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“…refs [23,24]) and often reasonable quantitative agreement is obtained. A less comprehensive comparison with experimental data exists on the angular distributions of sputtered atoms and the sputtering yield dependence on ion incidence angle [23,[25][26][27][28][29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Simulation of ion beam sputtering with SDTrimSP, TRIDYN and SRIM

Hofsäß

Zhang

Mutzke

2014

Applied Surface Science

152

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A quantitative simulation of ion beam sputtering and related collision cascade effects is essential for applications of ion beam irradiation in thin film deposition, surface treatment and sculpting with focused ion beams, ion beam smoothing of surfaces and ion-induced nanopattern formation. The understanding of fundamental ion-solid interaction processes relevant for nanostructure formation, ion-induced mass redistribution, sputter yield amplification, ion beam mixing and dynamic compositional changes requires reliable simulations of ion-solid interaction processes in particular at low ion energies.In this contribution we discuss the possibilities, the key benefits and the limitations of three popular binary collision Monto Carlo simulation programs (SDTrimSP, TRIDYN and SRIM).The focus will be set to the calculation of angle dependent sputter yields, angular distribution of sputtered particles, sputter yields for compound materials, sputter yield amplification effects, as well as the extraction of parameters relevant for modelling ion-induced surface pattern formation from vacancy and recoil atom distributions.

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“…(c) Comparison of high-energy part of Na ejecta distribution (dashed line) and SRIM simulations (solid line, for the assumed surface composition [see Goettel, 1988]) for E i = 1 keV. (d) SHEA energy spectra for Ar + of different E i on W at zero incident and ejection angles [Goehlich et al, 2000]. (e) Ejection of Na from Na 2 SO 4 for impacting Ar + of 3.5 keV and with E b ∼ 0.27 eV [Wiens et al, 1997].…”

Section: Production Of Sheamentioning

confidence: 99%

“…These ions may be partly neutralized and backscattered from the surface to space (up to 20% for light ions like the SW major components [see McComas et al, 2009;Wieser et al, 2009]), but a significant fraction of the incident ions, increasing with ions atomic mass number, can be implanted on the EB surface while ejecting a surface atom or molecule. Sputtering products from impacts of keV ions can have energies, peaking at few eV with a high-energy non-Maxwellian tail, up to at least several tens eV for a refractory material [Goehlich et al, 2000]. We refer to this component of the surface ejecta as sputtered high-energy atoms (SHEA).…”

Section: Introductionmentioning

confidence: 99%

Observing planets and small bodies in sputtered high-energy atom fluxes

et al. 2011

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[1] The evolution of the surfaces of bodies unprotected by either strong magnetic fields or thick atmospheres in the solar system is caused by various processes, induced by photons, energetic ions, and micrometeoroids. Among these processes, the continuous bombardment of the solar wind or energetic magnetospheric ions onto the bodies may significantly affect their surfaces, with implications for their evolution. Ion precipitation produces neutral atom releases into the exosphere through ion sputtering, with velocity distribution extending well above the particle escape limits. We refer to this component of the surface ejecta as sputtered high-energy atoms (SHEA). The use of ion sputtering emission for studying the interaction of exposed bodies (EB) with ion environments is described here. Remote sensing in SHEA in the vicinity of EB can provide mapping of the bodies exposed to ion sputtering action with temporal and mass resolution. This paper speculates on the possibility of performing remote sensing of exposed bodies using SHEA and suggests the need for quantitative results from laboratory simulations and molecular physic modeling in order to understand SHEA data from planetary missions. In Appendix A, referenced computer simulations using existing sputtering data are reviewed.

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Anisotropy effects in physical sputtering investigated by laser-induced fluorescence spectroscopy

Cited by 50 publications

References 21 publications

Production of negative ions on graphite surface in H2/D2 plasmas: Experiments and srim calculations

Production of negative ions on graphite surface in H2/D2 plasmas: Experiments and srim calculations

Simulation of ion beam sputtering with SDTrimSP, TRIDYN and SRIM

Observing planets and small bodies in sputtered high-energy atom fluxes

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