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Author Vanraes, P.; Parayil Venugopalan, S.; Besemer, M.; Bogaerts, A.
Title Assessing neutral transport mechanisms in aspect ratio dependent etching by means of experiments and multiscale plasma modeling Type A1 Journal Article
Year 2023 Publication Plasma Sources Science and Technology Abbreviated Journal Plasma Sources Sci. Technol.
Volume 32 Issue 6 Pages 064004
Keywords A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract Since the onset of pattern transfer technologies for chip manufacturing, various strategies have been developed to circumvent or overcome aspect ratio dependent etching (ARDE). These methods have, however, their own limitations in terms of etch non-idealities, throughput or costs. Moreover, they have mainly been optimized for individual in-device features and die-scale patterns, while occasionally ending up with poor patterning of metrology marks, affecting the alignment and overlay in lithography. Obtaining a better understanding of the underlying mechanisms of ARDE and how to mitigate them therefore remains a relevant challenge to date, for both marks and advanced nodes. In this work, we accordingly assessed the neutral transport mechanisms in ARDE by means of experiments and multiscale modeling for SiO<sub>2</sub>etching with CHF<sub>3</sub>/Ar and CF<sub>4</sub>/Ar plasmas. The experiments revealed a local maximum in the etch rate for an aspect ratio around unity, i.e. the simultaneous occurrence of regular and inverse reactive ion etching lag for a given etch condition. We were able to reproduce this ARDE trend in the simulations without taking into account charging effects and the polymer layer thickness, suggesting shadowing and diffuse reflection of neutrals as the primary underlying mechanisms. Subsequently, we explored four methods with the simulations to regulate ARDE, by varying the incident plasma species fluxes, the amount of polymer deposition, the ion energy and angular distribution and the initial hardmask sidewall angle, for which the latter was found to be promising in particular. Although our study focusses on feature dimensions characteristic to metrology marks and back-end-of-the-line integration, the obtained insights have a broader relevance, e.g. to the patterning of advanced nodes. Additionally, this work supports the insight that physisorption may be more important in plasma etching at room temperature than originally thought, in line with other recent studies, a topic on which we recommend further research.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001021250100001 Publication Date 2023-06-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 0963-0252 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.8 Times cited Open Access Not_Open_Access
Notes P Vanraes acknowledges funding by ASML for the project ‘Computational simulation of plasma etching of trench structures’. P Vanraes and A Bogaerts want to express their gratitude to Mark J Kushner (University of Michigan) for the sharing of the HPEM and MCFPM codes, and for the interesting exchange of views. P Vanraes wishes to thank Violeta Georgieva and Stefan Tinck for the fruitful discussions on the HPEM code, Yu-Ru Zhang for an example of the CCP reactor code and Karel Venken for his technical help with the server maintenance and use. S P Venugopalan and M Besemer wish to thank Luigi Scaccabarozzi, Sander Wuister, Coen Verschuren, Michael Kubis, Kuan-Ming Chen, Ruben Maas, Huaichen Zhang and Julien Mailfert (ASML) for the insightful discussions. Approved Most recent IF: 3.8; 2023 IF: 3.302
Call Number PLASMANT @ plasmant @c:irua:197760 Serial 8811
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Author Tampieri, F.; Gorbanev, Y.; Sardella, E.
Title Plasma‐treated liquids in medicine: Let's get chemical Type A1 Journal Article
Year 2023 Publication Plasma Processes and Polymers Abbreviated Journal Plasma Processes & Polymers
Volume 20 Issue 9 Pages e2300077
Keywords A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract Fundamental and applied research on plasma‐treated liquids for biomedical applications was boosted in the last few years, dictated by their advantages with respect to direct treatments. However, often, the lack of consistent analysis at a molecular level of these liquids, and of the processes used to produce them, have raised doubts of their usefulness in the clinic. The aim of this article is to critically discuss some basic aspects related to the use of plasma‐treated liquids in medicine, with a focus on their chemical composition. We analyze the main liquids used in the field, how they are affected by non‐thermal plasmas, and the possibility to replicate them without plasma treatment.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001005060700001 Publication Date 2023-06-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 1612-8850 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.5 Times cited Open Access Not_Open_Access
Notes We thank COST Actions CA20114 (Therapeutical Applications of Cold Plasmas) and CA19110 (Plasma Applications for Smart and Sustainable Agriculture) for the stimulating environment provided. Francesco Tampieri wishes to thank Dr. Cristina Canal for the helpful discussion during the planning stage of this paper. Approved Most recent IF: 3.5; 2023 IF: 2.846
Call Number PLASMANT @ plasmant @c:irua:197386 Serial 8814
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Author Morais, E.; Bogaerts, A.
Title Modelling the dynamics of hydrogen synthesis from methane in nanosecond‐pulsed plasmas Type A1 Journal article
Year 2024 Publication Plasma processes and polymers Abbreviated Journal Plasma Processes & Polymers
Volume 21 Issue 1 Pages
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A chemical kinetics model was developed to characterise the gas‐phase dynamics of H<sub>2</sub>production in nanosecond‐pulsed CH<sub>4</sub>plasmas. Pulsed behaviour was observed in the calculated electric field, electron temperature and species densities at all pressures. The model agrees reasonably with experimental results, showing CH<sub>4</sub>conversion at 30% and C<sub>2</sub>H<sub>2</sub>and H<sub>2</sub>as major products. The underlying mechanisms in CH<sub>4</sub>dissociation and H<sub>2</sub>formation were analysed, highlighting the large contribution of vibrationally excited CH<sub>4</sub>and H<sub>2</sub>to coupling energy from the plasma into gas‐phase heating, and revealing that H<sub>2</sub>synthesis is not affected by applied pressure, with selectivity remaining unchanged at ~42% in the 1–5 bar range.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001091258700001 Publication Date 2023-10-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 1612-8850 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.5 Times cited Open Access Not_Open_Access
Notes We gratefully acknowledge financial support by the Flemish Government through the Moonshot cSBO project “Power‐to‐Olefins” (P2O; HBC.2020.2620) and funding from the Independent Research Fund Denmark (project nr. 0217‐00231B). Approved Most recent IF: 3.5; 2024 IF: 2.846
Call Number PLASMANT @ plasmant @c:irua:201192 Serial 8983
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Author Bercx, M.; Mayda, S.; Depla, D.; Partoens, B.; Lamoen, D.
Title Plasmonic effects in the neutralization of slow ions at a metallic surface Type A1 Journal Article
Year 2023 Publication Contributions to Plasma Physics Abbreviated Journal Contrib. Plasma Phys
Volume Issue Pages
Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Abstract Secondary electron emission is an important process that plays a significant role in several plasma‐related applications. As measuring the secondary electron yield experimentally is very challenging, quantitative modelling of this process to obtain reliable yield data is critical as input for higher‐scale simulations. Here, we build upon our previous work combining density functional theory calculations with a model originally developed by Hagstrum to extend its application to metallic surfaces. As plasmonic effects play a much more important role in the secondary electron emission mechanism for metals, we introduce an approach based on Poisson point processes to include both surface and bulk plasmon excitations to the process. The resulting model is able to reproduce the yield spectra of several available experimental results quite well but requires the introduction of global fitting parameters, which describe the strength of the plasmon interactions. Finally, we use an in‐house developed workflow to calculate the electron yield for a list of elemental surfaces spanning the periodic table to produce an extensive data set for the community and compare our results with more simplified approaches from the literature.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001067651300001 Publication Date 2023-09-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 0863-1042 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.6 Times cited Open Access Not_Open_Access
Notes We acknowledge the financial support of FWO-Vlaanderen through project G.0216.14N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO-Vlaanderen and the Flemish Government-department EWI. Approved Most recent IF: 1.6; 2023 IF: 1.44
Call Number EMAT @ emat @c:irua:200330 Serial 8962
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Author Bogaerts, A.
Title Special Issue on “Dielectric Barrier Discharges and their Applications” in Commemoration of the 20th Anniversary of Dr. Ulrich Kogelschatz’s Work Type A1 Journal Article
Year 2023 Publication Plasma Chemistry and Plasma Processing Abbreviated Journal Plasma Chem Plasma Process
Volume 43 Issue 6 Pages 1281-1285
Keywords A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract n/a
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001110371000001 Publication Date 2023-11-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 0272-4324 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.6 Times cited Open Access Not_Open_Access
Notes n/a Approved Most recent IF: 3.6; 2023 IF: 2.355
Call Number PLASMANT @ plasmant @c:irua:201387 Serial 8969
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Author Lin, A.; Gromov, M.; Nikiforov, A.; Smits, E.; Bogaerts, A.
Title Characterization of Non-Thermal Dielectric Barrier Discharges for Plasma Medicine: From Plastic Well Plates to Skin Surfaces Type A1 Journal Article
Year 2023 Publication Plasma Chemistry and Plasma Processing Abbreviated Journal Plasma Chem Plasma Process
Volume 43 Issue 6 Pages 1587-1612
Keywords A1 Journal Article; Non-thermal plasma · Plasma medicine · Dielectric barrier discharge · Plasma diagnostics · Plasma surface interaction · In situ plasma monitoring; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract technologies have been expanding, and one of the most exciting and rapidly growing

applications is in biology and medicine. Most biomedical studies with DBD plasma systems are performed in vitro, which include cells grown on the surface of plastic well plates, or in vivo, which include animal research models (e.g. mice, pigs). Since many DBD systems use the biological target as the secondary electrode for direct plasma generation and treatment, they are sensitive to the surface properties of the target, and thus can be altered based on the in vitro or in vivo system used. This could consequently affect biological response from plasma treatment. Therefore, in this study, we investigated the DBD plasma behavior both in vitro (i.e. 96-well flat bottom plates, 96-well U-bottom plates, and 24-well flat bottom plates), and in vivo (i.e. mouse skin). Intensified charge coupled device (ICCD) imaging was performed and the plasma discharges were visually distinguishable between the different systems. The geometry of the wells did not affect DBD plasma generation for low application distances (≤ 2 mm), but differentially affected plasma uniformity on the bottom of the well at greater distances. Since DBD plasma treatment in vitro is rarely performed in dry wells for plasma medicine experiments, the effect of well wetness was also investigated. In all in vitro cases, the uniformity of the DBD plasma was affected when comparing wet versus dry wells, with the plasma in the wide-bottom wells appearing the most similar to plasma generated on mouse skin. Interestingly, based on quantification of ICCD images, the DBD plasma intensity per surface area demonstrated an exponential one-phase decay with increasing application distance, regardless of the in vitro or in vivo system. This trend is similar to that of the energy per pulse of plasma, which is used to determine the total plasma treatment energy for biological systems. Optical emission spectroscopy performed on the plasma revealed similar trends in radical species generation between the plastic well plates and mouse skin. Therefore, taken together, DBD plasma intensity per surface area may be a valuable parameter to be used as a simple method for in situ monitoring during biological treatment and active plasma treatment control, which can be applied for in vitro and in vivo systems.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001072607700001 Publication Date 2023-09-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 0272-4324 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.6 Times cited Open Access Not_Open_Access
Notes This work was partially funded by the Research Foundation—Flanders (FWO) and supported by the following Grants: 12S9221N (A. L.), G044420N (A. L. and A. B.), and G033020N (A.B.). We would also like to thank several patrons, as part of this research was funded by donations from different donors, including Dedert Schilde vzw, Mr Willy Floren, and the Vereycken family. We would also like to acknowledge the support from the European Cooperation in Science & Technology (COST) Action on “Therapeutical applications of Cold Plasmas” (CA20114; PlasTHER). Approved Most recent IF: 3.6; 2023 IF: 2.355
Call Number PLASMANT @ plasmant @c:irua:200285 Serial 8970
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Author Cangi, A.; Moldabekov, Z.A.; Neilson, D.
Title International Conference on “Strongly Coupled Coulomb Systems” (July 24-29, 2022, Görlitz, Germany) Type Editorial
Year 2023 Publication Contributions to plasma physics Abbreviated Journal
Volume 63 Issue 9-10 Pages e202300110-3
Keywords Editorial; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001100083800001 Publication Date 2023-11-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 0863-1042; 1521-3986 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.6 Times cited Open Access
Notes Approved Most recent IF: 1.6; 2023 IF: 1.44
Call Number UA @ admin @ c:irua:201156 Serial 9051
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Author Smith, G.J.; Diomede, P.; Gibson, A.R.; Doyle, S.J.; Guerra, V.; Kushner, M.J.; Gans, T.; Dedrick, J.P.
Title Low-pressure inductively coupled plasmas in hydrogen : impact of gas heating on the spatial distribution of atomic hydrogen and vibrationally excited states Type A1 Journal article
Year 2024 Publication Plasma sources science and technology Abbreviated Journal
Volume 33 Issue 2 Pages 025002-25020
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Non-equilibrium inductively coupled plasmas (ICPs) operating in hydrogen are of significant interest for applications including large-area materials processing. Increasing control of spatial gas heating, which drives the formation of neutral species density gradients and the rate of gas-temperature-dependent reactions, is critical. In this study, we use 2D fluid-kinetic simulations with the Hybrid Plasma Equipment Model to investigate the spatially resolved production of atomic hydrogen in a low-pressure planar ICP operating in pure hydrogen (10-20 Pa or 0.075-0.15 Torr, 300 W). The reaction set incorporates self-consistent calculation of the spatially resolved gas temperature and 14 vibrationally excited states. We find that the formation of neutral-gas density gradients, which result from spatially non-uniform electrical power deposition at constant pressure, can drive significant variations in the vibrational distribution function and density of atomic hydrogen when gas heating is spatially resolved. This highlights the significance of spatial gas heating on the production of reactive species in relatively high-power-density plasma processing sources.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001154851700001 Publication Date 2024-01-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 0963-0252 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.8 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 3.8; 2024 IF: 3.302
Call Number UA @ admin @ c:irua:203866 Serial 9054
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Author Albrechts, M.; Tsonev, I.; Bogaerts, A.
Title Investigation of O atom kinetics in O2plasma and its afterglow Type A1 Journal Article
Year 2024 Publication Plasma Sources Science and Technology Abbreviated Journal Plasma Sources Sci. Technol.
Volume 33 Issue 4 Pages 045017
Keywords A1 Journal Article; oxygen plasma, pseudo-1D plug-flow kinetic model, O atoms, low-pressure validation, atmospheric pressure microwave torch; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract We have developed a comprehensive kinetic model to study the O atom kinetics in an O<sub>2</sub>plasma and its afterglow. By adopting a pseudo-1D plug-flow formalism within the kinetic model, our aim is to assess how far the O atoms travel in the plasma afterglow, evaluating its potential as a source of O atoms for post-plasma gas conversion applications. Since we could not find experimental data for pure O<sub>2</sub>plasma at atmospheric pressure, we first validated our model at low pressure (1–10 Torr) where very good experimental data are available. Good agreement between our model and experiments was achieved for the reduced electric field, gas temperature and the densities of the dominant neutral species, i.e. O<sub>2</sub>(a), O<sub>2</sub>(b) and O. Subsequently, we confirmed that the chemistry set is consistent with thermodynamic equilibrium calculations at atmospheric pressure. Finally, we investigated the O atom densities in the O<sub>2</sub>plasma and its afterglow, for which we considered a microwave O<sub>2</sub>plasma torch, operating at a pressure between 0.1 and 1 atm, for a flow rate of 20 slm and an specific energy input of 1656 kJ mol<sup>−1</sup>. Our results show that for both pressure conditions, a high dissociation degree of ca. 92% is reached within the discharge. However, the O atoms travel much further in the plasma afterglow for<italic>p</italic>= 0.1 atm (9.7 cm) than for<italic>p</italic>= 1 atm (1.4 cm), attributed to the longer lifetime (3.8 ms at 0.1 atm vs 1.8 ms at 1 atm) resulting from slower three-body recombination kinetics, as well as a higher volumetric flow rate.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001209453500001 Publication Date 2024-04-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 0963-0252 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.8 Times cited Open Access
Notes This research was supported by the Horizon Europe Framework Program ‘Research and Innovation Actions’ (RIA), Project CANMILK (Grant No. 101069491). Approved Most recent IF: 3.8; 2024 IF: 3.302
Call Number PLASMANT @ plasmant @c:irua:205920 Serial 9125
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Author Leigh, S.; Doyle, S.J.; Smith, G.J.; Gibson, A.R.; Boswell, R.W.; Charles, C.; Dedrick, J.P.
Title Ionization and neutral gas heating efficiency in radio frequency electrothermal microthrusters : the role of driving frequency Type A1 Journal article
Year 2024 Publication Physics of plasmas Abbreviated Journal
Volume 31 Issue 2 Pages 023509-23513
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The development of compact, low power, charge-neutral propulsion sources is of significant recent interest due to the rising application of micro-scale satellite platforms. Among such sources, radio frequency (rf) electrothermal microthrusters present an attractive option due to their scalability, reliability, and tunable control of power coupling to the propellant. For micropropulsion applications, where available power is limited, it is of particular importance to understand how electrical power can be transferred to the propellant efficiently, a process that is underpinned by the plasma sheath dynamics. In this work, two-dimensional fluid/Monte Carlo simulations are employed to investigate the effects of applied voltage frequency on the electron, ion, and neutral heating in an rf capacitively coupled plasma microthruster operating in argon. Variations in the electron and argon ion densities and power deposition, and their consequent effect on neutral-gas heating, are investigated with relation to the phase-averaged and phase-resolved sheath dynamics for rf voltage frequencies of 6-108 MHz at 450 V. Driving voltage frequencies above 40.68 MHz exhibit enhanced volumetric ionization from bulk electrons at the expense of the ion heating efficiency. Lower driving voltage frequencies below 13.56 MHz exhibit more efficient ionization due to secondary electrons and an increasing fraction of rf power deposition into ions. Thermal efficiencies are improved by a factor of 2.5 at 6 MHz as compared to the more traditional 13.56 MHz, indicating a favorable operating regime for low power satellite applications.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001207449000001 Publication Date 2024-02-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 1070-664x ISBN Additional Links UA library record; WoS full record
Impact Factor 2.2 Times cited Open Access
Notes Approved Most recent IF: 2.2; 2024 IF: 2.115
Call Number UA @ admin @ c:irua:205506 Serial 9156
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Author Chai, Z.-N.; Wang, X.-C.; Yusupov, M.; Zhang, Y.-T.
Title Unveiling the interaction mechanisms of cold atmospheric plasma and amino acids by machine learning Type A1 Journal article
Year 2024 Publication Plasma processes and polymers Abbreviated Journal
Volume Issue Pages 1-26
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma medicine has attracted tremendous interest in a variety of medical conditions, ranging from wound healing to antimicrobial applications, even in cancer treatment, through the interactions of cold atmospheric plasma (CAP) and various biological tissues directly or indirectly. The underlying mechanisms of CAP treatment are still poorly understood although the oxidative effects of CAP with amino acids, peptides, and proteins have been explored experimentally. In this study, machine learning (ML) technology is introduced to efficiently unveil the interaction mechanisms of amino acids and reactive oxygen species (ROS) in seconds based on the data obtained from the reactive molecular dynamics (MD) simulations, which are performed to probe the interaction of five types of amino acids with various ROS on the timescale of hundreds of picoseconds but with the huge computational load of several days. The oxidative reactions typically start with H-abstraction, and the details of the breaking and formation of chemical bonds are revealed; the modification types, such as nitrosylation, hydroxylation, and carbonylation, can be observed. The dose effects of ROS are also investigated by varying the number of ROS in the simulation box, indicating agreement with the experimental observation. To overcome the limits of timescales and the size of molecular systems in reactive MD simulations, a deep neural network (DNN) with five hidden layers is constructed according to the reaction data and employed to predict the type of oxidative modification and the probability of occurrence only in seconds as the dose of ROS varies. The well-trained DNN can effectively and accurately predict the oxidative processes and productions, which greatly improves the computational efficiency by almost ten orders of magnitude compared with the reactive MD simulation. This study shows the great potential of ML technology to efficiently unveil the underpinning mechanisms in plasma medicine based on the data from reactive MD simulations or experimental measurements. In this study, since reactive molecular dynamics simulation can currently only describe interactions between a few hundred atoms in a few hundred picoseconds, deep neural networks (DNN) are introduced to enhance the simulation results by predicting more data efficiently. image
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001202061200001 Publication Date 2024-04-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition (up)
ISSN 1612-8850 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.5 Times cited Open Access
Notes Approved Most recent IF: 3.5; 2024 IF: 2.846
Call Number UA @ admin @ c:irua:205512 Serial 9181
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