Oxygen Recombination Probability Data for Plasma-Assisted Atomic Layer Deposition of SiO2and TiO2
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2021-04-22
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en
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9
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Journal of Physical Chemistry C, Volume 125, issue 15, pp. 8244–8252
Abstract
Atomic layer deposition (ALD) can provide nanometer-thin films with excellent conformality on demanding three-dimensional (3D) substrates. This also holds for plasma-assisted ALD, provided that the loss of reactive radicals through surface recombination is sufficiently low. In this work, we determine the surface recombination probability r of oxygen radicals during plasma ALD of SiO2 and TiO2 for substrate temperatures from 100 to ∼240 °C and plasma pressures from 12 to 130 mTorr (for SiO2). For both processes, the determined values of r are very low, i.e., ∼10-4 or lower, and decrease with temperature and pressure down to ∼10-5 within the studied ranges. Accordingly, deposition on trench structures with aspect ratios (ARs) of <200 is typically not significantly limited by recombination and obtaining excellent film conformality is relatively facile. For higher AR values, e.g., approaching 1000, the plasma time needed to reach saturation increases exponentially and becomes increasingly dependent on the process conditions and the corresponding value of r. Similar dependence on process conditions can be present for plasma ALD of other materials as well, where, in certain cases, film growth is already recombination-limited for AR values of ∼10. Radical recombination data and trends as provided by this work are valuable for optimizing plasma ALD throughput and feasibility for high-AR applications and can also serve as input for modeling of radical recombination mechanisms.Description
Funding Information: This work is part of the research program HTSM with Project No. 15352, which is (partly) financed by the Netherlands Organization for Scientific Research (NWO). R.L.P. acknowledges funding from Academy of Finland, ALDI project, decision no. 331082. VTT Technical Research Centre of Finland Ltd. and Dr. M. Utriainen are acknowledged for supplying the PillarHall LHAR3 and LHAR4 conformality test structures. Lam Research Corp. is acknowledged for providing vertical trench nanostructures. Solliance and the Dutch province of Noord Brabant are acknowledged for funding the TEM facility. Finally, the authors thank Dr. M.A. Verheijen for the TEM imaging, Dr. B. Barcones Campo for the FIB preparation of the TEM sample, and C. van Helvoirt for the technical support. Publisher Copyright: © 2021 The Authors. Published by American Chemical Society. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
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Arts, K, Deijkers, S, Puurunen, R L, Kessels, W M M & Knoops, H C M 2021, ' Oxygen Recombination Probability Data for Plasma-Assisted Atomic Layer Deposition of SiO 2 and TiO 2 ', Journal of Physical Chemistry C, vol. 125, no. 15, pp. 8244–8252 . https://doi.org/10.1021/acs.jpcc.1c01505