Influence of surface roughness on the sputter yield of Mo under keV D ion irradiation

JOURNAL OF NUCLEAR MATERIALS

卷:555

Article

Kelemen, M.^1,2  Schwarz-Selinger, T.³  Mutzke, A.⁴  Balden, M.³  Vassallo, E.⁵  Pedroni, M.⁵  Dellasega, D.^5,6  Passoni, M.^5,6  Romeo, F.^5,6  Hakola, A.⁷  Pelicon, P.¹  Zaplotnik, R.¹  Markelj, S.¹ 

[1] Jozef Stefan Inst, Jamova 39, SI-1000 Ljubljana, Slovenia

[2] Jozef Stefan Int Postgrad Sch, Jamova Cesta 39, Ljubljana 1000, Slovenia

[3] Max Planck Inst Plasma Phys, Boltzmannstr 2, D-85748 Garching, Germany

[4] Max Planck Inst Plasma Phys, Wendelsteinstr 1, D-17491 Greifswald, Germany

[5] CNR, Ist Sci & Tecnol Plasmi, Via Roberto Cozzi 53, I-20125 Milan, Italy

[6] Politecn Milan, Via Ponzio 34-3, I-20133 Milan, Italy

[7] VTT Tech Res Ctr Finland Ltd, POB 1000, Espoo, Finland

关键词: Ion beam;    Deuterium;    RBS;    Sputter yield;    Surface roughness;    Angular dependence;   

DOI  :  10.1016/j.jnucmat.2021.153135

来源: Elsevier

【 摘 要 】

In this work the influence of surface roughness on the sputter yield of Mo under keV D ion bombardment was investigated for different impact angles. For this purpose, thin films of Mo (similar to 120 nm) were deposited by pulsed laser deposition onto graphite substrates with varying surface roughness (Ra ranging from 5 nm to 2-3 mu m). The as-deposited samples were irradiated at room temperature by 3 keV D-3(+) ions originating from an electron-cyclotron-resonance ion gun. Samples were exposed to D ions at angles between 0 degrees and 70 degrees and fluences in range of 10(23) D/m(2). The areal densities of the Mo marker layers were determined with Rutherford backscattering spectroscopy. For all the surfaces we observed a strong angular dependence of the sputter yield. For smooth and intermediate surface roughnesses, up to Ra similar to 280 nm, we obtained an increase of the sputter yield with the angle up to a factor of five compared to 0 degrees. In contrast, at the highest surface roughness in the 2-3 mu m range the sputtering yield decreases with increasing impact angle. The obtained data were compared to SDTrimSP-3D simulations. We obtained good agreement between the simulated and experimental sputter yield for surfaces for which we could provide high resolution atomic force microscopy (AFM) surface representations. As high-resolution surface mapping was not possible for surface roughness of 2-3 mu m, we found large deviation between the calculation and the measured data. The combination of measured and simulated data represent important input for predicting the erosion rates of surfaces at inner walls of thermonuclear fusion devices, which are expected to change surface roughness over time by sustained plasma exposure. (C) 2021 Elsevier B.V. All rights reserved.

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