Molecular size effect in the chemical sputtering of a-C:H thin films by low energy H+, H2+, and H3+ ions

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:269

Article; Proceedings Paper

Meyer, F. W.¹  Jacob, W.²  Schwarz-Selinger, T.²  von Toussaint, U.² 

[1] Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA

[2] EURATOM, Max Planck Inst Plasmaphys, D-85748 Garching, Germany

关键词: Sputtering;    Ion-surface collisions;    Chemical erosion;    Carbon-based materials;    Divertor materials;    a-C:H thin films;   

DOI  :  10.1016/j.nimb.2010.12.071

来源: Elsevier

【 摘 要 】

We have experimentally determined total carbon yields per incident H atom in the energy range 36300 eV/H for H+, H-2(+), and H-3(+) projectiles incident normally on similar to 60 nm thick a-C:H films, using 2-D ellipsometry determination of erosion crater volumes ex vacua, the separately characterized thin film carbon density, and the incident beam current integration accumulated on target during the crater evolution. During each beam exposure, methane production was monitored using in situ quadrupole mass spectrometry (QMS). The present total carbon yields/H for incident H ions obtained via ellipsometry are in agreement with total mass loss measurements for H-3(+) by Balden and Roth [1] over the investigated energy range. The observed methane production per incident H for the molecular ions exhibits molecular size effects over the entire energy range investigated, confirming the trend observed in the ellipsometry-based total C yields/H. (C) 2011 Elsevier B.V. All rights reserved.

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