Book of abstracts

RSD2018 is organized by the research group DRAFT.The mission statement of the research group DRAFT (Dedicated Researchon Advanced Films and Targets) reads “At DRAFT we want to becomethe recognized leader in the understanding of thin film growth by re-active magnetron sputtering and to enjoy research by experiments andsimulations.” More information on this research group can be found onwww.draft.ugent.be

Book of abstracts

Dedicated to all attendees who make this meeting again an interesting scientifichappening.

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Table of contents

Welcome and Schedule 1Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Thursday December 6th, 2018 . . . . . . . . . . . . . . . . . . . 3Friday December 7th, 2018 . . . . . . . . . . . . . . . . . . . . 5

Invited talks 11A. Matthews : Property and Evaluation Considerations for the

Development of Tribological Coatings . . . . . . . . . . . 13M. Ahlgren : Design of PVD coatings for cutting tools . . . . . 15N. Radic : Magnetron Sputtered Thin Films for Green Energy 16A. Palmero : Magnetron Sputtering Deposition of Porous Thin

Films at Oblique Geometries: Fundamentals and Applica-tions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

K. Nordlund : Insights on sputtering from molecular dynamicssimulations . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Oral presentations 25C. Schiffers : Multinary HiPIMS . . . . . . . . . . . . . . . . . 27S .Krassnitzer : Industrialization of Reactive High Power Impulse

Magnetron Sputtering . . . . . . . . . . . . . . . . . . . . 28I. Caretti : AC magnetron sputtering of metallic versus ceramic

rotatable targets – a comparative study . . . . . . . . . . 30P. Kelly : R-HiPIMS deposition of TiO2 onto flexible substrates

for the photocatalytic removal of contaminants of emergingconcern from water . . . . . . . . . . . . . . . . . . . . . . 32

M. Licklederer : Reactive magnetron-sputtered TiO2 rutile filmsas flat model system for plasmonic systems . . . . . . . . 33

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A. Panepinto : Synthesis of anatase(core)/rutile(shell) nanos-tructured TiO2 thin films by DC and high power impulsemagnetron sputtering for dye-sensitized solar cell applica-tions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

C. Esparza Contro : Chemical composition, microstructure andcorrosion resistance of titanium oxide thin films obtainedcontinuously by reactive sputtering in an inverted cylindri-cal magnetron . . . . . . . . . . . . . . . . . . . . . . . . . 35

A. Dulmaa : Copper oxide thin films deposited by reactive mag-netron sputtering . . . . . . . . . . . . . . . . . . . . . . . 37

S. M. Deambrosis : Wear resistant Ta-Al-N coatings depositedvia reactive HiPIMS . . . . . . . . . . . . . . . . . . . . . 38

M. Masłyk : Influence of deposition conditions on dopants con-centration in GaN thin films obtained by room temperatureRF magnetron sputtering . . . . . . . . . . . . . . . . . . 40

B. Bouteille : Kinetics of phase separation in barium borosilicateglass thin films deposited by magnetron sputtering . . . . 42

P. Moskovkin : A glancing angle reactive deposition of TiO2on non-flat substrates: the prediction of morphology andoptical properties by means of kinetic Monte Carlo method 43

V. Gervilla : Toward a universal understanding of thin metalfilm growth dynamics on weakly-interacting substrates . . 44

P. Hatton : Modelling Bubble Formation in sputter depositedCdTe Solar Cells . . . . . . . . . . . . . . . . . . . . . . . 46

R. Tonneau : Reactive magnetron sputtering of TiOx thin filmsdeposited from metallic and ceramic (TiO1.9) targets: a dif-ferential study . . . . . . . . . . . . . . . . . . . . . . . . 48

T. Nyberg : Process modeling of non-saturated reactive sputter-ing processes . . . . . . . . . . . . . . . . . . . . . . . . . 49

R. Schelfhout : A low deposition rate in poisoned mode: a trivi-ality? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

F. Lofaj : Hybrid reactive deposition of W-C:H coatings by DCand High Power Impulse Magnetron Sputtering . . . . . . 52

J. Rezek : High-rate reactive high-power impulse magnetronsputtering of In-Ga-Zn-O and ZnO:Al thin films at low sub-strate temperature . . . . . . . . . . . . . . . . . . . . . . 53

T. Shimizu : Evolution of ion flux composition in reactive HiP-IMS of zirconium oxide under peak current regulation bypulse frequency control . . . . . . . . . . . . . . . . . . . . 54

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Table of contents

R.P. Viloan : Enhancement of film properties by controlling theion energy distribution using Bipolar HiPIMS . . . . . . . 55

H. Gerdes : Reactive HIPIMS: Controlling stoichiometry andionization . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Posters 59V. Linss : Towards Industrial Deposition of Metal Oxides for Pas-

sivating and Carrier Selective Contacts: MoOx Depositedby Industrial Size Reactive DC Magnetron Sputtering andIndustrial Size Linear Evaporation Source . . . . . . . . . 61

N. Britun : Diagnostics of magnetron target cleaning process bylaser-based spectroscopy . . . . . . . . . . . . . . . . . . 62

M. A. Gharavi : Synthesis and Characterization of (Ti, Mg)NThin Films . . . . . . . . . . . . . . . . . . . . . . . . . . 64

M. Mickan : Control of the texture of gadolinia-doped ceria thinfilms in reactive magnetron sputtering . . . . . . . . . . . 66

S. Fryska : Influence of gas composition used for ion cleaningstep on diffusion layer formation during S-phase coatingdeposition on austenitic stainless steel . . . . . . . . . . . 67

J. M. Voronkoff : Study of the Ni migration from sub-nanometriclayer to thicker a zinc oxide layer . . . . . . . . . . . . . . 68

Q. Herault : In situ measurement setup to study thin film growthdeposited by reactive magnetron sputtering. . . . . . . . . 69

B. Paul : Growth of nanoporous Ca3Co4O9 thin films preparedby reactive rf-magnetron sputtering followed by post an-nealing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

A.V. Kaziev : Deposition of aluminum oxide coatings in a high-current magnetron discharge with millisecond-scale pulses 71

S. Konstantinidis : Can we use the Normalized Energy Flux tocontrol the microstructure of reactively sputtered titaniumdioxide thin films? . . . . . . . . . . . . . . . . . . . . . . 72

H. Montigaud : Characterization of the porosity of silicon nitridethin layers deposited by reactive magnetron sputtering . . 73

S.Hejazi : Reactive sputtered TiO2 thin film with highly controlover crystalline structure for photocatalytic H2 evolution . 74

S. Azhani : The effect of pulse frequency under peak currentregulation in reactive HiPIMS of magnesium oxide . . . . 75

J. Muller : Optical and electrical properties of AZO coating de-posited by reactive magnetron sputtering: application toc-Si thin film solar cells . . . . . . . . . . . . . . . . . . . 76

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D. Thoen : Uniformity of reactively sputtered NbTiN for mi-crowave kinetic inductance detectors . . . . . . . . . . . . 77

K. Strijckmans : The (in)stability of process control mechanismsin reactive DC sputtering deposition . . . . . . . . . . . . 78

T. Kozak : Modelling reactive HiPIMS deposition with fixed av-erage power and varying pulse frequency . . . . . . . . . . 79

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Welcome and Schedule

Welcome and Schedule

Dear colleagues,

It is a great pleasure to notice that the interest for the conference se-ries Reactive Sputter Deposition has not eroded over time, probably dueto a good protecting thin film. This meeting still attracts a good blendof engineers and scientists, researchers with an academic and industrialbackground, old and young researchers. I would like to especially welcomethese young people. As they have already discovered, or will discover dur-ing this meeting, reactive sputter deposition is a fascinating research field.It requires an open mind to learn from several approaches ranging fromphysics, over chemistry to material science. It is fun to notice that a train-ing in a specific field is not sufficient to solve fundamental questions or toovercome technical problems when you apply this technique to grow thinfilms.For the Ghent team this RSD2018 is a special one as we celebrate its 10th

anniversary. I still remember the first meeting in the lecture room at thedepartment in 2000. This long track record and success is only possiblewith the support of companies that wish to present their products on eachmeeting. Please meet them at their booth. They have fascinating productsto show. Also, the institutional sponsors should not be forgotten: the fac-ulty of Sciences, Ghent University, and the research community “Surfacemodification of materials”. I also wish to thank the members of DRAFT toassist in the organization. My last “thank you” goes to you as participant.Learn, discuss, and enjoy.

For the organizing committee,

Diederik Depla

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Welcome and Schedule

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-7-

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Welcome and Schedule

-8-

Welcome and Schedule

-9-

Welcome and Schedule

-10-

Invited talks

Invited talks

Property and evaluation considerations for thedevelopment of tribological coatings

A. Matthews1 and A. Leyland2

1 School of Materials and ICAM, University of Manchester, ICAM-Pariser Build-ing, Manchester M1 6BB, UK

2 Dept of Materials Science and Engineering, University of Sheffield, Sheffield, S13JD, UK

It is now recognised that most tribological contacts involve several wearmechanisms, and this has led to the development of “rules” of surfacedesign based on the type of contact (i.e. static load, unidirectional slid-ing, reciprocating sliding/fatigue, fretting, abrasion, impact, corrosion).For each of these contact types, rules and requirements can be identifiedwhich allow the performance to be optimised [1,2]. When an applicationinvolves several contact types acting together, the rules can be combined.Coupled with the development of such design rules, there has been signif-icant progress over recent years in the understanding of the requirementsfrom coatings and surface treatments to fulfil these rules. The capabil-ity to produce surfaces to meet the design rules has been assisted by therecent availability of advanced plasma-based coating and treatment pro-cesses. The different types of tribological contacts are described and therules identified to mitigate wear in each case are outlined (with examples ofsuitable coatings in each case). A mechanical properties approach to wearreduction is emphasized [3,4,5,6,7]. This identifies the benefits of coatingswhich have a high ratio between their hardness (H) and modulus (E), whichtherefore possess a long “elastic strain to failure” and can thus toleratelarge substrate deformations (be they elastic or plastic) without yielding;they also exhibit high resilience and toughness (as quantified by an abilityto absorb energy without fracture) The need to increase the “H/E” ratiois now embedded in coating development programmes in many laborato-ries, and it is recognized that new plasma-assisted PVD nanocompositemetal-metal and ceramic-metal coatings offer particular promise, as theycan possess “near-ceramic” hardness levels, but elastic moduli nearer tothe (low) levels exhibited by the typical bulk materials used in engineeringcomponents. With these new insights and processes, novel nanostructuredfilms (and load-supporting “duplex” surface diffusion layers plus coatings)can be created using plasma techniques, which provide scope to ensurethat coatings can survive under heavy loading conditions and provide ex-

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Invited talks

ceptional wear resistance [6-13]. Details are given about nanocompositeand glassy-metal coatings which can enhance the wear and friction per-formance. The benefits of electron beam evaporation and sputter-basedprocesses are mentioned.

[1] K Holmberg and A Matthews, Tribology of Engineered Surfaces, In Wear - Mate-rials, Mechanisms and Practice (Ed.G W Stachowiack), John Wiley and Sons Ltd,Chichester, UK, (2005). ISBN-13: 978-0-470-01628-2.

[2] K Holmberg and A Matthews. “Coatings Tribology: Properties, Mechanisms, Tech-niques and Applications in Surface Engineering”, 2nd Edition, ISBN: 978-0-444-52750-9, Elsevier, Amsterdam, 2009.

[3] A. Matthews and A. Leyland, “Materials related aspects of nanostructured tribo-logical coatings”, SVC Bulletin (2009) p40. (Spring 2009 Issue; http://www.svc.org/Publications). (Also in: Proceedings of the 51st SVC Ann. Tech. Conf. (2008) 744-750. (Chicago, Il, 19–24 April 2008) pub. SVC, Albuquerque, 2008; ISSN 0737-5921).

[4] A.Matthews and A.Leyland. The future of plasma-based surface engineering tech-niques in tribology. Proc. World Tribology Congress III : Vol.2 (2005) 297. pub.ASME Intl; ISBN 0791842029.

[5] A.Leyland and A.Matthews. On the significance of the H/E ratio in wear control :A nanocomposite approach to optimised tribological behaviour. Wear 246 (2000) 1.

[6] A.Leyland and A.Matthews. Design criteria for wear-resistant nanostructured andglassy-metal coatings. Surf.Coat.Technol. 177-178 (2004) 317.

[7] A.Leyland and A.Matthews. Optimisation of nanostructured tribological coatings,in: “Hard Nanostructured Coatings” (Chapter 12) J.T.M. deHosson and A. Cav-aleiro (Eds.) Springer (2006). ISBN 0-387-25462-3.

[8] M Audronis, A Matthews, A Leyland, “Pulsed-bias magnetron sputtering of non-conductive crystalline chromia films at low substrate temperature”. J Phys D: ApplPhys, 41, 1-10, (2008).

[9] G Cassar, A Matthews, A Leyland, Triode plasma diffusion treatment of titaniumalloys, Surf. Coat.Technol. 212 (2012) 20-31.

[10] B Attard, A Matthews, A Leyland , G Cassar, “Enhanced surface performance ofTi-6Al-4V alloy using a novel duplex process combining PVD-Al coating and triodeplasma oxidation”. Surf Coat Technol. 257 (2014) 154-164.

[11] X. Liu, J. Kavanagh, A. Matthews, A. Leyland, The combined effects of Cu and Agon the nanostructure and mechanical properties of CrCuAgN PVD coatings, Surf.Coat. Technol., 284 (2015) 101-111.

[12] J. Lawal, P. Kiryukhantsev-Korneev, A. Matthews, A. Leyland, Mechanical prop-erties and abrasive wear behaviour of Al-based PVD amorphous/nanostructuredcoatings, Surf. Coat. Technol., 310 (2017) 59-69.

[13] X.Liu, C Iamvasant, C Liu, A. Matthews, A. Leyland, CrCuAgN PVD nanocompos-ite coatings: Effects of annealing on coating morphology and nanostructure, App.Surf. Sci., 392 (2017) 732-746.

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Invited talks

Design of PVD coatings for cutting tools

M. Ahlgren1

1 AB Sandvik Coromant

The lifetime of high performance cutting tools and wear parts can beconsiderable extended by applying thin wear resistant coatings. There isan extended variety of protective coatings, which properties are tailoredfor specific applications. Chemical vapour deposition (CVD) and physicalvapour deposition (PVD) are established industrial techniques for deposi-tion of wear resistant thin layers on cutting tools and wear parts. Generally,the main goal is to optimize material properties aiming at reducing wear,friction, oxidation and corrosion. The choice of deposition technique, thechemical composition of the coating material as well as process parame-ters will influence coating properties such as thickness, morphology, tex-ture, residual stresses among others. These properties will ultimately affecttheir adhesion to the substrates and wear resistance.

This talk will start with a short introduction to coatings for cutting toolsdiscussing both the history and the state of the art of CVD and PVD.Thereafter the focus of the presentation will shift to PVD coated gradesfor metal cutting using indexable inserts. Important aspects concerningthe design of these PVD coatings will be discussed.

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Invited talks

Magnetron Sputtered Thin Films for Green Energy

N. Radic1

1 Rudjer Boskovic Institute, Div. Materials Physics, Bijenicka 54, Zagreb, Croatia

Green energy comes from renewable natural sources – sunlight, wind, hy-dropower, geothermal, biomass, tides - readily available all over the worldand exhibiting smaller impact on the environment than widely used fossilfuels. The efforts to exploit the most copious energy source available –solar irradiation – are already advanced to the stage when photovoltaicdevices are the third renewable energy source in terms of global capacity.However, renewable energy sources are inherently intermittent in nature,and variable in time. One way to controlled consumption of the PV energyis by converting it into storable hydrogen for later use. Hydrogen – itself apromising green fuel – can be produced directly by photocatalysis of waterunder sunlight and with efficient catalyst. Both photovoltaic and pho-tocatalytic materials can be prepared by magnetron sputtering, and twopertinent examples will be elaborated below. A promising emerging photo-voltaics include Quantum dot solar cell. Quantum dots have bandgaps thatare tunable across a wide range of energy levels by changing the dots’ size.This property makes QDs attractive for multi-junction solar cells, wherea variety of materials are used to improve efficiency by harvesting multi-ple portions of the solar spectrum. Materials consisting of semiconductorcore-shell nanostructures, like nanowires or quantum dots attract specialattention due to their highly adjustable electronic structure and opticalproperties. Especially interesting for the application of such materials insolar cells is the fact that Ge/Si core/shell quantum dots have a type IIband alignment, leading to the separation of charge carriers [1]. We haverecently developed a method for the growth of self-assembled core/shellGe/Si quantum dots in an amorphous alumina matrix [2]. Tuning the ra-dius of the Ge core and thickness of the Si shell allows to tune the positionof the absorption peak in a broad range of energies [3], making this com-posite material very promising for the applications in solar cells. A greenalternative to production of hydrogen by electrolysis is a direct solar watersplitting. Tantalum oxynitrides combine band gap reduction and aqueousstability required for practical use as catalyst in water splitting [4]. ThinTaON films have been prepared by reactive dc magnetron sputtering undermixed Ar+N2+O2 atmosphere. By regulating the partial pressures of theN2 and O2 gases, the anion stoichiometry of the TaON film is systemati-

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Invited talks

cally controlled. The optical characterization of the TaON films allowed todetermine the bandgap. It was found that only Ta oxynitride films with acomposition close to stoichiometric TaON exhibit energy gap potentiallyuseful in water splitting processes.

[1] E. L. Oliveira et al., J.Phys. Chem C 116, 4399–4407, (2012)[2] M. Buljan et al., Nanotechnology 26, 065602, (2015)[3] N. Nekic et al., Nanophotonics 6, 1055-1062, (2017)[4] K. Salamon, N. Radic, I. Bogdanovic Radovic, M. Ocko, JPD-AD 49, 195301, (2016)

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Invited talks

Magnetron Sputtering Deposition of Porous ThinFilms at Oblique Geometries: Fundamentals andApplications

A. Palmero1

1 Materials Science Institute of Seville (CSIC-US)

The magnetron sputtering technique operated at oblique geometries hasrecently emerged as an invaluable tool for the deposition of porous thinfilms [1]. Not only it has managed to reproduce similar film morphologiesthan those found by classical evaporation methods, but also to widen thevariety of porous nanostructures available by fine tuning the plasma con-ditions: from tilted nanocolumnar arrays to sponge-like structures, passingthrough compact films with tilted porous networks [2]. In this presenta-tion, an up to date description of its fundamentals and nanostructurationpossibilities are given along with numerous potential applications wherethese films are incorporated into functional devices. Indeed, the large spe-cific surface of the layers, associated to the existence of large open micro-and mesopores, make them ideal candidates whenever an interaction witha gaseous, solid or liquid medium is required.

Applications in sensor devices, e.g. cholesterol or glucose, or in biomedicine,where the film surface energy can be tailored to allow the growth of liv-ing cells while inhibiting bacterial proliferation, will be envisioned [3].Moreover, applications in optofluidics, where the optical response of multi-layered structures (photonic crystals) may be tuned when different liquidspass through the porous channels, will be discussed [4]. Results are based

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Invited talks

on, but not limited to, the activities of the Nanotechnology on Surfacesresearch group, which involves computer simulations, fundamental exper-iments as well as the development of laboratory-size functional devicestargeting specific applications.

[1] A. Barranco, A. Borras, A. R. Gonzalez-Elipe, A. Palmero, Progress in MaterialsScience 76, 59 (2016)

[2] J. M. Garcia-Martin, R. Alvarez,P. Romero-Gomez, A. Cebollada and A. Palmero,Appl. Phys. Lett. 97, 173103 (2010)

[3] I. Izquierdo-Barba, J.M. Garcıa-Martin, R. Alvarez, A. Palmero, J. Esteban, C.Perez-Jorge, D. Arcos, M. Vallet-Regi, Acta Biomaterialia. 15, 20 (2015)

[4] Manuel Oliva-Ramirez, Angel Barranco, Markus Loffler, Francisco Yubero, AgustinR. Gonzalez-Elipe, ACS Nano, 10 1256 (2016)

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Invited talks

Insights on sputtering from molecular dynamicssimulations

K. Nordlund1

1 Department of Physics and Helsinki Institute of Physics, University of Helsinki,Finland

While the basic physics of sputtering in the linear cascade regime has beenknown for a long time, many other varieties of sputtering have started tobe understood only more recently. In this talk, I will overview the currentunderstanding of physics and physico-chemistry of sputtering induced byenergetic ions. Sputtering is here defined as surface erosion processes thatoccur only if the incoming particle has a kinetic energy higher than somethreshold value. The basic linear cascade sputtering from keV energy ionscan be understood well based on binary collision approximation simula-tions [1]. However, quantitative prediction of sputtering yields is challeng-ing in this method, as the yields depend strongly on the so called surfacebinding energy, which is a free parameter. I will describe molecular dynam-ics (MD) simulations, in which this quantity is inherently described by theinteratomic potential, and hence this method is better suited for predictivemodelling. I will critically discuss how reliable the MD simulations are forsputtering modelling.

In the last about 3 decades it has become clear that there are many otherphysical sputtering mechanisms than pure linear cascade physical sputter-ing. In dense materials, keV ions induce dense heat spikes, and sputteringcan be strongly enhanced in these spikes due to explosive and liquid flowemission of material. I will show examples of emission of large atom clus-ters from heat spikes induced by single ion impacts [2], and recent work ofsputtering yields exceeding 1000 from Au nanowires [3]. I will also showthat the sputtered clusters are so hot that they evaporate atoms, and asignificant fraction of these redeposit on the surface (leading to the amus-ing observation of negative sputtering yields in a time-dependent analysis).Even for low energy ions, thermal effects can lead to enhancement of thesputtering when the sample temperature approaches the melting temper-ature [4,5]. Although this effect is not fully understood, it is likely relatedto ion-induced formation of adatoms, which evaporate at elevated temper-atures.

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Invited talks

Figure 1. Swift chemical sputtering of carbon. A D ion (red) incoming from theside attacks a carbon-carbon chemical bond, which breaks due to energy transferfrom the ion.

I will also describe the swift chemical sputtering mechanism [6]. Thisphysico-chemical mechanism can explain the sputtering of carbon by low-energy (down to 5 eV) hydrogen ions coming from fusion plasmas, whichwas long considered a major mystery, see Fig. 1. I will present a simpleanalytical model calculation of the energy transfer in breaking single chem-ical bonds, which shows that swift chemical sputtering is fundamentallydifferent from both physical sputtering and reactive etching [7]. I will fi-nally show that, contrary to initial beliefs [8], this mechanism can actuallyalso lead to chemical sputtering of metals [9].

[1] M. Hou and M. T. Robinson, Applied physics 18 (1979) 381[2] K. Nordlund et al, Nucl. Instr. Meth. Phys. Res. B 206, 189 (2003)[3] G. Greaves et al, Phys. Rev. Lett. 111, 065504 (2013)[4] J. Hinks et al, Scientific Reports 8, 512 (2018) [[5] T. Metspalu et al, Nucl. Instr. Meth. Phys. Res. B 415, 31 (2018)[6] E. Salonen, K. Nordlund, J. Keinonen, and C. H. Wu, Phys. Rev. B 63, 195415

(2001)[7] A. V. Krasheninnikov et al, Comput. Mater. Sci 25, 427 (2002)[8] K. Nordlund et al, Pure and Applied Chemistry 78, 1203 (2006)[9] C. Bjorkas et al, New J. Phys. 11, 123017 (2009)

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Invited talks

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Invited talks

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Oral presentations

Oral presentations

Multinary HiPIMS

T. Leyendecker1, W. Kolker1, S. Bolz1, C. Schiffers1

1 CemeCon AG, Adenauerstrasse 20A4, 52146 Wurselen, Germany

The almost unlimited choice of materials is one of the biggest strength ofHiPIMS. It offers a variety of opportunities for tailoring coatings by alloy-ing of the chemical composition or by using species from certain elementsto densify the film by heavy ion bombardment. Carbon based coatingsare mainly used for tribological applications. However, coatings such asTiCN and WC/C are of high relevance for tap tool applications – a mar-ket of about 100 Mio tools per year. Commercial coating products forthe threading industry are most frequently multilayer designs of an AlTiNwith a carbon containing top layer. This gives HiPIMS a new challenge:multinary coatings of materials with rather different properties.

This paper will introduce a new HiPIMS control concept offering for everysource an individual set of HiPIMS pulse parameters. Now the coating de-signer can take the very different ionization potential of different materialsinto account or select a source for heavy ion bombardment while the otherones are optimized for highest sputtering rate.

All this with full synchronization of the HiPIMS cathodes to the HiPIMStable bias. Hence, the film’s designer can actively go for the ionized targetspecies while suppressing the incorporation of sputtering gas into the film.

Data from plasma analysis as well as hardness and stress measurementreveal a huge effect of the pulse parameters such as frequency and pulselength on the film properties.

Multinary HiPIMS gives freedom to coating engineers and broadens theapplication range of HiPIMS. Case stories from the thread tool industryunderline the industrial relevance of the concept.

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Oral presentations

Industrialization of Reactive High Power ImpulseMagnetron Sputtering

S. Krassnitzer1, D. Kurapov1

1 Oerlikon Surface Solutions AG, Iramali 18, LI-9496 Balzers Liechtenstein

High Power Impulse Magnetron Sputtering is nowadays a proven technol-ogy to close a performance gap between Arc Evaporation and MagnetronSputtering. ARC Evaporation is a very robust and reproducible techniqueto deposit high quality metal, nitride, oxide and carbohydrate films, butemission of droplets can be a big drawback in some industrial applicationsas special cutting applications, metal forming and plastic processing. HiP-IMS as a magnetron sputtering process achieves the same ionization levelsof the sputtered material and very dense hard and smooth coatings arepossible.

When it comes to reactive sputtering the effects on target poisoning arerelevant and requests for more, well-known control of the sputtering pro-cess. In principle, you have to stabilize the partial pressure of your reactiveworking gas in order to define the working point. What is simple to solvein a Lab coating system become difficult and costly when considering forbatch coating systems.

IV-curve of HiPIMS discharge de-rived by long S3PTM power pulses Demonstration of disappearance of

hysteresis with long pulses at highpower density

In this presentation, we are explaining the unique properties of the S3pTM

Technology with regard to reactive High Power Impulse Sputtering. S3pTM

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Oral presentations

Scalable Pulsed Power Plasma. S3pTM means that pulse power density andpulse length is independently adjustable. Pulses are applied as power pulsesand not as voltage pulses as in in conventional HIPIMS. Long pulses of5 ms to 50 ms duration and power density of up to 2 KW/cm2 enables inreactive processes to eliminate the hysteresis effect. A detailed discussionof the working principles and an introduction to the coating products andcoating system is further given.

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Oral presentations

AC magnetron sputtering of metallic versus ceramicrotatable targets – a comparative study

I. Caretti1, D. Debruyne1, F. Fack1, R. van Nuffel1, G. Gobin1, W. DeBosscher1

1 Soleras Advanced Coatings BVBA, E3 Laan 75/79, 9800 - Deinze, Belgium

One of the most significant changes in the sputter coating market wasmarked by the introduction of rotating cylindrical targets, which allow forhigher material utilization and higher power density as compared to planartargets. Since then, AC magnetron sputtering of metallic rotatable targetsin reactive mode has become a worldwide used technique for the depositionof dielectric layers with applications in the fields of architectural glass, flatpanel displays, solar cells, etc. Over the last decade, thin film manufactur-ing has witnessed a growing tendency towards the replacement of metallicrotatable sputter targets by ceramic ones. Given the insulating nature ofceramics, this has been largely possible thanks to the parallel developmentof high-end power supplies with more advanced arc management settings.

Dynamic deposition rate and target voltage versus oxygen flow for Zr (left panel)and ZrOx (right panel) rotary targets (taken from J. Oberste-Berghaus, R. VanNuffel, K. De Jaeger, A. Das, W. De Bosscher, 58th Annual Technical Con-ference Proceedings of the Society of Vacuum Coaters, SVC, Santa Clara, April2015)

In principle, the sputtering of ceramic targets may have several advan-tages relative to their metallic counterparts: i) little or no hysteresis andhence a more stable working point, ii) little or no use of reactive gas duringsputtering (less cross-talking with adjacent sputter compartments in theproduction line), and iii) often a higher deposition rate. However, sinceceramic materials are generally brittle and electrically non-conductive, themanufacturing of mechanically tough, sputterable cylindrical targets re-

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Oral presentations

mains a challenge. Understanding the relationship between the materialproperties and the final sputtering characteristics is crucial for the tai-lored fabrication of ceramic sputter targets.

In this work, we will show a comprehensive study of the sputtering behaviorof different metal oxide targets, such as ZnSnOx, ZrOx, etc, prepared bythermal spray processes at Soleras Advanced Coatings. The sputteringcharacteristics will be compared with the corresponding metallic versionsof these targets and the use of different AC power supplies will be discussed.The composition, structure and optical properties of the deposited films isalso analyzed.

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Oral presentations

R-HiPIMS deposition of TiO2 onto flexible substratesfor the photocatalytic removal of contaminants ofemerging concern from water

R. B. P. Marcelino1, C. C. Amorim1, M. Ratova2, B. Delfour-Peyrethon1,P. Kelly1

1 Universidade Federal de Minas Gerais, School of Engineering, Department ofEnvironmental and Sanitation Engineering, Research Group on EnvironmentalApplications of Advanced Oxidation Processes, Av. Antonio Carlos, 6627, BeloHorizonte – MG, Brazil

2 Surface Engineering Group, Manchester Metropolitan University, Faculty of Sci-ence and Engineering, Manchester, M1 5GD, U.K.

Thin films of titanium dioxide (TiO2) were deposited onto polyethyleneterephthalate (PET) for use as photocatalytic surfaces to remove contami-nants of emerging concerns (CECs) from water. The nanocrystalline TiO2thin films were deposited in a single stage process using the reactive highpower impulse magnetron sputtering (R-HiPIMS) technique. The filmswere characterized by different techniques (SEM/EDS, STEM, AFM, UV-Vis spectroscopy), and their wettability was assessed via water dropletcontact angle measurements. The photocatalytic activity was assessed bythe degradation of two model CECs: the fungicide carbendazim (CBZ),a systemic benzimidazole fungicide highly consumed worldwide and theanthropogenic pollution tracer caffeine (CAF). The process was also pho-tosensitized by a natural and non-hazardous source of curcumin (turmeric).The results show that the PET- TiO2 surfaces reached up to 35% of CBZand 39% of CAF removal under UV-A and visible radiation under mildconditions. The surfaces remained stable for 5 consecutive cycles of use,with similar kinetic rates. The species involved in the photocatalytic reac-tions were investigated by use of h+, HO• and •O−2 trapping agents, bothin the presence and absence of turmeric. The results indicated that theaddition of the turmeric led to an increase in photogenerated •O−2 radicalsdue to a synergistic effect between the photocatalyst and the photosensi-tizer. The degradation process was also studied by ESI-MS in high reso-lution and the structures of the intermediates were proposed. The resultsdemonstrate the potential of the PET-TiO2 surfaces as a straightforwardsolution for the removal of CECs from water using an easily formable andscalable, reusable new photocatalytic surface.

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Oral presentations

Reactive magnetron-sputtered TiO2 rutile films as flatmodel system for plasmonic systems

M. Licklederer1, M. Altomare1 N. Truong Nguyen1, H. Park2, M. Halik2,S. Hejazi1, P. Schmuki1,3

1 Department of Materials Science and Engineering, Institute for Surface Scienceand Corrosion WW4-LKO, University of Erlangen-Nuremberg, Martensstrasse7, D-91059 Erlangen, Germany

2 Department of Material Science and Engineering, Institute of Polymer Mate-rials, University of Erlangen-Nuremberg, Martensstrasse 7, D-91059 Erlangen,Germany

3 Chemistry Department, Faculty of Sciences, King Abdul-Aziz University, 80203Jeddah, Saudi Arabia

Flat TiO2/Ti stacked layers, with a surface roughness of <1 nm are de-posited by (reactive) magnetron sputtering on Si wafer substrates. Boththe TiO2 (top) layer and the Ti (bottom) layer are 75 nm thick. TheTiO2/Ti architectures are then sputter-coated with thin Au films (thick-ness ¬ 10 nm) that are converted into Au nanoparticles by solid statedewetting through a suitable thermal treatment [1]. Size and spacing ofthe dewetted Au nanoparticles can be controlled by adjusting the initialthickness of the Au film. The thermal treatment leads at the same time tocrystallization of the TiO2 layer into rutile phase. The Au-decorated rutileTiO2 layers enable plasmonic photoelectrochemical water splitting undervisible light illumination (450-750 nm range). The photo-electrochemicalwater splitting performance is maximized for rutile TiO2 layers decoratedwith ∼30 nm-sized Au particles [2].

[1] M. Altomare, N. T. Nguyen and P. Schmuki, Chemical science, 2016, 7, 6865–6886[2] M. Valenti, M. P. Jonsson, G. Biskos, A. Schmidt-Ott and W. A. Smith, J. Mater.

Chem. A, 2016, 4, 17891–17912[3] N. Wu, Nanoscale, 2018, 10, 2679–2696;

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Oral presentations

Synthesis of anatase(core)/rutile(shell) nanostructuredTiO2 thin films by DCMS and HIPIMS fordye-sensitized solar cell applications

A. Panepinto1, M. Michiels2, A. Zintler3, L. Molina-Luna3,C. Bittencourt1, P.-A. Cormier1, R. Snyders1,2

1 Chemistry of Plasma-Surface Interactions, University of Mons, 20 Place du Parc,7000 Mons, Belgium

2 Materia Nova Research Center, 3 Avenue Nicolas Copernic, 7000 Mons, Belgium3 Department of Materials and Earth Sciences, Electron Microscopy Center Darm-

stadt, Technische Universitat Darmstadt, Karolinenplatz 5, 64289 Darmstadt,Germany

Nowadays, anatase-rutile core shell structures are well recognized as highlyefficient for TiO2 based catalysts or photoelectrodes of the dye-sensitizedsolar cells (DSSCs).In particular, for a DSSC the thin layer of rutile covering the core anatasecolumn would be benefit to the device performance by promoting thecharge transfer between the nanostructured photoanode and the sensitizer.In this work, we therefore propose to synthesize such nanostructured TiO2thin films by reactive magnetron sputtering at glancing angle modulatingthe power applying mode. Pure anatase and well separated columns arefirst synthesized in DC mode, and then high pulse peak power is appliedto the target (high power impulse magnetron sputtering – HiPIMS) tocover the columns by a thin layer of rutile. The latter technique is in factwell-known to improve the energy brought to the growing film which isa key parameter to successfully obtain the high temperature TiO2 phase,i.e. rutile. The peak current, the frequency and the pulse width are opti-mized in order to control the crystalline structure and the thickness of therutile top layer. Scanning Electron Microscopy cross section views of thesynthesized films give clear evidence that even when is bombarded by highenergetic particles created during the HiPIMS process the nanostructureis kept. Grazing Incidence X-Ray Diffraction also reveal the presence ofboth anatase and rutile in the films. The evolution of the main anataseand rutile diffraction peaks with the X-Ray incidence angle would indicatethat the rutile is concentrated at the top surface of the material. Furthercharacterization of the crystalline structure interface has been performedby a Transmission Electron Microscopy (TEM) mapping with a HAADFdetector and confirm the latter hypothesis.

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Oral presentations

Chemical composition, microstructure and corrosionresistance of titanium oxide thin films obtainedcontinuously by reactive sputtering in an invertedcylindrical magnetron

C. Esparza Contro1,2, L. Latu-Romain1, G. Berthome1, C. Vachey2, M.Mantel1,2

1 Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble, France2 Ugitech SA, Ugine, France

Ti-based coatings for colored steel wire meet a market demand but theoptical properties of these films are of interest only if the mechanical andchemical durability of these coatings is satisfactory. This study aims to de-termine the influence of different process parameters, namely the oxygenflow rate and the substrate temperature on the chemical composition, mi-crostructure and corrosion resistance of titanium oxide thin films. The thinfilms of a hundred nanometers thickness are continuously deposited in aninverted cylindrical magnetron by reactive sputtering on moving stainlesssteel wires.

The increase of oxygen flow rate in the deposition chamber leads to a tran-sition between the metallic and poisoned mode and partial poisoning ofthe cylindrical cathode due to magnet rings gives rise to a step in the hys-teresis curve. The microstructures of the thin films have been investigatedby EPMA (Electron Probe Micro Analysis), XPS (X-Ray PhotoelectronSpectroscopy), grazing incidence X-Ray Diffraction (GIXRD) and TEMmicroscopy coupled with ASTAR technique.

Titanium oxide films exhibit a bilayer architecture in relation to a non-uniform plasma during deposition. This bilayer consists in an internalhexagonal TiOx layer containing interstitial oxygen in low concentrationand an upper layer made of rutile TiO2. An increase in oxygen flow rateleads to a transition from columnar to equiaxed polycrystalline structureand small grains (∼15 nm) are observed in the rutile phase. Controllingthe oxygen flow rate and the substrate temperature is a way to achieve athickness ratio between the two films and different functionalizations of thestainless steel wires are obtained in term of colored and localized corrosionresistance. The presence of a titanium underlying film is also discussed interm of corrosion resistance.

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Oral presentations

ASTAR-TEM orientation map of a Ti + TiOx thin film on 316L stainless steel

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Oral presentations

Copper oxide thin films deposited by reactivemagnetron sputtering

A. Dulmaa1, H. Vrielinck1, D. Depla1

1 Department of Solid State Science, Ghent University, Krijgslaan 281/S1, B-9000Gent, Belgium

Copper oxide thin films are grown by reactive DC magnetron sputtering inargon/oxygen mixtures at room temperature. The influence of the oxygenpartial pressure, the total pressure, and the discharge current was investi-gated on the phase formation at the constant pumping speed. The phasecomposition was characterized by X-ray diffraction and Fourier trans-form infrared spectroscopy. A clear change from pure copper, over cuprite(Cu2O), and paramelaconite (Cu4O3) to tenorite (CuO) thin films withincreasing oxygen partial pressure was observed. The main driving forcedefining the phase composition is the oxygen partial pressure. The influ-ence of the discharge current in the range 0.2-0.5 A was minimal. Thedischarge current affects both the thermal flux towards the growing film,and the deposition rate, and permits in this way to modify the energy perarriving atom (EPA). As such the EPA hardly changes within the certainoxygen partial pressure range studied for all phases.

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Oral presentations

Wear resistant Ta-Al-N coatings deposited via reactiveHiPIMS

S. M. Deambrosis1, E. Miorin1, F. Montagner1, V. Zin1, L. Litti2, M.Meneghetti2

1 National Research Council of Italy - Institute of Condensed Matter Chemistryand Technologies for Energy, Corso Stati Uniti, 4, 35127 Padova, Italy

2 University of Padova – Department of Chemical Sciences, Via Marzolo, 1, 35131Padova, Italy

Ta-N (Ta at.%∼40, N at.%∼60) and Ta-Al-N (Ta at.%∼25, Al at.%∼15, Nat.%∼60) coatings were deposited on Si coupons via reactive HiPIMS froma pure Ta target and a Ta/Al (50/50 at.%) source respectively. Workingparameters (p = 1 Pa, N2/(Ar+N2) = 0.5, P = 500 W, T = 200 C) werekept constant with the exception of the applied substrate bias voltage,which was varied from -50 to -100 V to improve mechanical and tribologicalproperties.

In particular, comparing the two sets of coatings, hardness and elasticmodulus were considerably higher for Ta-Al-N films, while their wear re-sistance (w) was about 20 times lower.

In the light of these results, the authors tried reducing N2/(Ar+N2) ratio(form 0.5 to 0.05) during sputtering to optimize w. The best result wasachieved at N2/(Ar+N2) = 0.05 (i.e. 5% N2). For this specimen, the vari-ation in ionization fraction and transport behavior of different species ledto a clear deviation of deposited film composition [1]. Indeed, going downto the 5% of N2, the coating composition changed (very low Al and Nat.%), microstructure varied, mechanical properties slightly improved (Hfrom ∼27 (about 15 at.% Al content) to 30 GPa (about 1 at.% Al con-tent)), wear resistance raised significantly (more than 60 times greater).Focusing on the wear tracks (ball-on-flat reciprocating mode), the authorsobserved roll-like debris for all specimens. Combining SEM-EDS and Ra-man analyses, they found:

i high w Ta-Al-N sample (∼ 15 at.% Al): as soon as the nitride startedoxidizing, it came off the film surface (debris were oxidized but nooxygen was detected into the wear track)

ii low w coatings (Ta-N and Ta-Al-N containing ∼1 at. % Al): theoxide layer peeled off only when the oxygen level was sufficiently high

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Oral presentations

(greatly oxidized debris plus oxygen detected into the wear track).Therefore, the formed TaxOy seemed to act as a lubricant.

[1] B. C. Zheng, Z. L. Wu, B. Wu, Y. G. Li, M. K. Lei, A global plasma model for reac-tive deposition of compound films by modulated pulsed power magnetron sputteringdischarges, Journal of Applied Physics 121 (2017) 171901

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Oral presentations

Influence of deposition conditions on dopantsconcentration in GaN thin films obtained by roomtemperature RF magnetron sputtering

M. Masłyk1, E. Kamińska1, R. Jakieła2, K. Pągowska1, O. Dyczewska2

1 Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw, Poland2 Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668

Warsaw, Poland

Properties of GaN thin films, particularly transport properties, are influ-enced by background impurities concentration, their electronic state andthe way of incorporation into the material [1]. Undoped GaN films haveusually n-type conductivity due to unintentional incorporation of O donordopant, while enhancement of electron conductivity is usually obtainedby doping with Si. The presence of foreign atoms being acceptor dopantsin GaN thin films, may inhibit achieving electron conductivity. Therefore,the precise control of residual doping in the process of magnetron sputter-deposition is crucial for obtaining required GaN films properties. Moreover,there are still open questions about process-property relationship concern-ing GaN films deposited by magnetron sputtering.

In this work we studied the influence of deposition conditions of reac-tive magnetron sputtering in a RF mode on the properties of GaN thinfilms. We used for comparison reason home-made, monocrystalline, 3 inchSi-doped GaN target (GaN:Si (1019 at/cm3) pieces sticked to Si wafer)and commercial (nominally) undoped, polycrystalline, 3 inch GaN target,which turned out to contain 1.3 at.% Fe after RBS investigation. 100 nmthick GaN films were deposited at RT, at N2/Ar+N2 ratio from the rangeof 6-100%, at total pressure from 0.5 to 3 Pa and cathode current of 100-175 mA. The properties of films were characterized by means of structural(XRD), electrical (sheet resistance), transport (Hall effect) and chemicalcomposition (RBS, SIMS) analyses. XRD studies showed polycrystallinestructure with dominant 0002 GaN diffraction line of GaN films obtainedusing GaN:Fe target, while changing from amorphous to polycrystallinewith increasing N2/Ar+N2 ratio (at 40%) in the case of GaN:Si target.Chemical investigations revealed Ga to N ratio close to 1 with significantconcentration of O and Si shallow donor dopants as well as Fe and Cdeep acceptor dopants in the range of 1019-1022 at/cm3. Based on cor-relation of dopants concentration and deposition conditions we observed

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lower concentration of these elements in films deposited at mixed atmo-sphere. GaN films obtained using GaN:Fe and GaN:Si targets were eithersemi-insulating or high-resistivity semiconducting, respectively, which pre-sumably is caused by self-compensation phenomena.

This research was supported by the statutory fund for young researchersof Institute of Electron Technology.

[1] P. Pampili, P.J. Parbrook, Doping of III-nitride materials, Materials Science inSemiconductor Processing 62 (2017) 180-191

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Oral presentations

Kinetics of phase separation in barium borosilicateglass thin films deposited by magnetron sputtering

B. Bouteille1,2, E. Gouillart1, D. Vandembroucq2, H. Montigaud1,E. Burov1, J.-T. Fonne3

1 Unite mixte CNRS/Saint-Gobain Surface du Verre et Interfaces (SVI), CNRSUMR125, 39 quai Lucien Lefranc - BP 135 F 93303 Aubervilliers Cedex, France

2 Laboratoire de Physique et Mecanique des Milieux Heterogenes (PMMH), CNRSUMR 7636, Sorbonne Universite 7 quai Saint-Bernard, Paris, France

3 Saint-Gobain Research Paris, 39 quai Lucien Lefranc, Aubervilliers, France

Liquid/liquid phase separation has already been studied in bulk glasseswhere the morphological evolution of phase domains during the coarseningstage are of particular interest. Growth law highly depends on the mor-phology of domains. When droplets are formed, they grow due to Ostwaldripening and their size scales with time to the one third. The coarseningof interconnected domains is controlled by hydrodynamic transport mech-anisms, so that the characteristic size scales linearly with time.From a process point of view, industrial glass surfaces are often func-tionalized by magnetron sputtering. Metallic and dielectric thin films aredeposited in order to add new optical, morphological or mechanical prop-erties. That is why in this study we investigate phase separation in glassthin films in order to use this phenomenon as a surface nano-structuringmethod. To understand kinetics and mechanisms of phase separation, thinlayers of barium borosilicate glass (SiO2-BaO-B2O3) are deposited byAr/O2 RF magnetron sputtering with thickness range between 10 and800 nm. They were studied after annealing at high temperature, between700C to 1000C. Growth kinetics of droplets has been determined byAFM and SEM. Thanks to Python image processing, sta-tistical datashowed a good agreement between both techniques. Growth kinetics inbarium borosilicate glass thin films are found significantly slower com-pared to the bulk and the distribution of particles’ sizes points out anauto-similar process. As in bulk glasses, composition, temperature and an-nealing time impact the final morphology of phase separation. Besides wehave observed that droplets growth is also influenced by additional pa-rameters such as initial glass layer thickness and hygrometry. In particularSIMS profiles helped to understand impact of room hygrometry on sam-ple. All these parameters allow to control morphologies and size of objectsobtained by phase separation.

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Oral presentations

A glancing angle reactive deposition of TiO2 onnon-flat substrates: the prediction of morphology andoptical properties by means of kinetic Monte Carlomethod

J. Muller1,P. Moskovkin1, S. Lucas1

1 University of Namur (PMR-LARN), rue de Bruxelles 61, B-5000 Namur, Belgium

Simulation of glancing angle magnetron sputtering deposition of TiO2 hasbeen performed on substrates exhibited different features by means of ki-netic Monte Carlo code NASCAM [1]. The model takes into account inci-dent fluxes of metallic and reactive individually. Both metallic and reactivefluxes may consist of atoms as well as ions having their own energy and an-gular distributions. Titanium atoms are supposed to have relatively highenergy; their flux to the substrate is directional. At the same time, theoxygen atoms are regarded as fully thermalized and their angular distri-bution is uniform. Also the sticking conditions for titanium and oxygenare different.Because of the shadowing effect, the surface features cause the growthof columnar structures during glancing angle deposition. The morphologyof growing film depends on the size and spatial distribution of the pre-existed surface features [2]. Thus by changing the surface treatment onecan obtain the film with the desired properties. In the present work, weanalyze optical properties of the film as a function of the initial surfacemorphology. Optical properties of the simulated film have been evaluatedusing two methods: the first one is the Transfer-Matrix method coupled todifferent effective medium models (Maxwell-Garnett and/or Bruggeman).The second method is the ADE-FDTD [3], which allows predicting opti-cal phenomena like light trapping or evanescent waves scattering. It hasbeen shown that the transmittance of the simulated samples is the func-tion of the film morphology thus strongly depends on the features whichpre-existed before the deposition.

[1] R. Tonneau, P. Moskovkin, A. Pflug, S. Lucas, J. Phys. D. Appl. Phys. 51 (2018)195202

[2] A. Palmero et al, Magnetron Sputtering Depositions at Oblique Angles on SeededSubstrates for the Development of sub-Micron Structural and Chemical Patterns,PSE 2018, Germany

[3] J. Muller, G. Parent, G. Jeandel, D. Lacroix, J. Opt. Soc. Am. A, Vol. 28, pp868-878. (2011)

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Toward a universal understanding of thin metal filmgrowth dynamics on weakly-interacting substrates

V. Gervilla1, B. Lu1, G. Almyras1, J. Greene2,3, K. Sarakinos1

1 Nanoscale Engineering Division, Department of Physics, Chemistry and Biology,Linkoping University, SE 581 83, Linkoping, Sweden

2 Thin Film Physics Division, Department of Physics, Chemistry and Biology,Linkoping University, SE-581 83 Linkoping, Sweden

3 Materials Science and Physics Departments, University of Illinois, Urbana, Illi-nois, 61801, USA

Growth of thin metal films with controlled morphology on weakly-in-teracting 2D material (e.g. graphene and MoS2) and oxide (e.g., SiO2,TiO2, ZnO) substrates is an essential step in the fabrication of novel high-performance microelectronic, photonic, and catalytic devices. This requiresa universal understanding of the atomic-scale processes that govern the dy-namics of film morphological evolution, from island nucleation to formationof a continuous film. In the present work, we contribute to this understand-ing using a combination of experiments, growth simulations, and analyti-cal modelling, to study growth of silver (Ag) films on SiO2 substrates. Weshow, by means of in situ growth monitoring and ex situ real-space imag-ing, that films exhibit a pronounced 3D morphology, which is controlledby either island nucleation or island coalescence, depending on the inter-play between vapor arrival and adatom diffusion rates [1]. Subsequently,we study nucleation and growth of single islands using kinetic Monte-Carlo(kMC) simulations [2]. The results show that 3D island shapes evolve ina self-similar manner, exhibiting a constant height-to-radius aspect ratio,which is a function of the growth temperature. Furthermore, our resultsreveal the following chain of atomic-scale events that lead to compact 3Disland shapes: 3D nuclei are first formed due to facile adatom ascent atsingle-layer island steps, followed by the development of sidewall facetsbounding the islands, which in turn facilitates upward diffusion from thebase to the top of the islands. The limiting atomic process which deter-mines the island height, for a given number of deposited atoms, is thetemperature-dependent rate at which adatoms cross from sidewall facetsto the island top. The latter results in an increased top-layer nucleationprobability with increasing temperature [3]. This explains experimentalobservations for film growth on weakly-interacting substrates [1], whichare not consistent with classical homoepitaxial growth theory, and is alsoconfirmed by an analytical mean-field model [3]. Finally, we simulate coa-

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lescence of faceted 3D island pairs in the presence of a deposition flux onweakly-interacting substrates using kMC [4]. We find that, during coales-cence, the initial faceted structure is maintained, which leads to formationof a facet-facet intersection in the neck formed between the two islands.The island reshaping proceeds via repeated facet migration, in which mo-bile adatoms provided by the deposition flux play a crucial role. We elu-cidate this role by combining kMC data with thermodynamic arguments,which provides a new theoretical framework for explaining experimentaldata on film morphology evolution.

[1] B. Lu, V. Elofsson, E.P. Munger, and K. Sarakinos, Appl. Phys. Lett. 105, 233113(2014)

[2] B. Lu, G.A. Almyras, V. Gervilla, J.E. Greene, and K. Sarakinos, Phys. Rev. M. 2,063401 (2018)

[3] V. Gervilla, G.A. Almyras, F. Thunstrom, J.E. Greene, and K. Sarakinos, Phys.Rev. M., submitted (2018)

[4] V. Gervilla, B. Lu, G.A. Almyras, and K. Sarakinos, unpublished data

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Oral presentations

Modelling Bubble Formation in sputter depositedCdTe Solar Cells

P. Hatton1, R. Smith1, P. M. Panchmatia1 and M. Walls1.

1 School of Science and CREST, Loughborough University, Loughborough, LE113TU, UK

Magnetron sputtering is an effective way of creating Thin Film coatings.In particular, thin film Cadmium Telluride (CdTe) is a promising, low costmaterial for a solar cell that can be deposited using pulsed DC MagnetronSputtering. The current research cell efficiency of a CdTe cell is 22.1% butwith a theoretical maximum of 30% and a band gap of 1.49 eV, CdTe is anideal candidate for a solar cell [1]. However, after sputtering, analysis shows4% of the working gas, Argon, is incorporated into the film. This causeslarge surface blisters between 3 and 50 nanometres in size post annealing at450C during a cadmium chloride treatment to remove stacking faults [2].This is a barrier which stands in the way of efficient CdTe cell productionvia this comparatively low-cost method. Micrographs of the blisters andthe internal bubbles in the thin film are shown in the figure below.

Left. Surface blisters after annealing and CdCl treatment. Right. subsurface bub-bles after annealing.

The aim is therefore to use computational modeling to explain the mech-anisms by which these bubbles form and make recommendations on howto minimize this effect. To achieve this we use Molecular Dynamics (MD)to find threshold energies for which the incident Argon will deposit into

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the lattice across 3 different crystal surface orientations, (100), (110) and(111). Calculations using the Nudged Elastic Band (NEB) methodologyhave determined that Argon can diffuse through a perfect lattice with anenergy barrier of 0.6 eV which is reduced when 4% Ar is included. MDsimulations of the high temperature annealing process show that Argonbubbles grow through diffusion and trap mutation mechanisms. Bubblesize distributions are determined as a function of annealing times and acomparison to other inert working gases in the magnetron, such as Xe,show reduced bubble effect. Finally, preliminary results using the adaptiveKinetic Monte Carlo developed at Loughborough University [3], which sim-ulates CdTe thin film growth over realistic time scales, demonstrates howArgon might be incorporated into the thin film during deposition.

[1] W. Shockley and H. Queisser, “Detailed Balance Limit of Efficiency of pn JunctionSolar Cells”, Journal of Applied Physics, vol. 32, no. 3, pp. 510-519, 1961

[2] P. M. Kaminski, S. Yilmaz, A. Abbas, F. Bittau, J. W. Bowers, R. C. Greenhalgh,and M. Walls, “Blistering of magnetron sputtered thin film CdTe devices,” in Pro-ceedings of IEEE 44th PVSC, 2017

[3] A.L. Lloyd, Y. Zhou, M. Yu, C. Scott, R. Smith, S.D. Kenny, “Reaction pathwaysin atomistic models of thin film growth”, The Journal of Chemical Physics 147,152719 (2017); doi: 10.1063/1.4986402

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Reactive magnetron sputtering of TiOx thin filmsdeposited from metallic and ceramic (TiO1.9) targets:a differential study

R. Tonneau1, P. Moskovkin1, V. Delchevalerie1, W. De Bosscher3,A. Pflug2, S. Lucas1

1 Namur University (LARN-PMR), Rue de Bruxelles 61, B-5000 Namur, Belgium2 Fraunhofer Institute for Surface Engineering and Thin Films (IST), Bienroder

Weg 54E, 38108 Braunschweig, Germany3 Soleras Advanced Coatings, E3 Laan 75/79 9800 Deinze, Belgium

This work reports an experimental and modeling study of the growth mech-anisms involved in TiOx thin film deposition by DC magnetron sputteringfrom both metallic and TiO1.9 targets. Isotopic 16O2 is used as reactive gasfor deposition in order to differentiate oxygen originating from ceramic tar-gets and from the gas phase. Differential analysis is possible thanks to ionbeam analysis techniques such as Rutherford Backscattering Spectroscopyto precisely analyze Ti, 16O and 18O content of the samples. Other investi-gation techniques such as AFM and SEM were also involved to characterizethe deposited coatings on samples either not tilted or tilted at 70.

In a second part, modeling tools are used to put in relation discharge andcoating’s properties. Three different multiscale modeling methods wereused: DSMC, PIC-MC and kMC. Each one is handling a defined step ofthe process, respectively (i) neutral particle motion, (ii) charged particlemotion and (iii) film growth. We will compare results between simulationsand experimental investigations. This work helps to better understand thegrowth of oxide layers by reactive magnetron sputtering and how plasmaparameters influence coating properties.

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Process modeling of non-saturated reactive sputteringprocesses

T. Nyberg1, S. Berg1

1 Solid State Electronics, The Angstrom Laboratory, Uppsala University, Box 534,751 21 Uppsala, Sweden

Numerous results for process modeling of reactive sputtering of oxides andnitrides have been published. All of these models clearly point out thatfor a large supply of the reactive gases the compositions of the depositedfilms will saturate at the compound stoichiometric values of the oxides ornitrides. Further, the transition from metallic rich films to compound richfilms normally exhibits a hysteresis like behavior. The situation is some-what different when e.g. carrying out reactive sputtering of Ti in a mixtureof argon and some hydrocarbon gas. In this case there is a possibility thatcarbon may be incorporated in the deposited film both chemically bondedto Ti to form the TiC compound but also as free non-reacted carbon. TiCmay be formed by direct chemical reactions between metallic Ti and thereactive gas. However, also carbon atoms plasma deposited from the hy-drocarbon gas may react to form TiC and some of the plasma generatedcarbon will be deposited as free non-reacted carbon. Due to the plasmageneration of carbon there will be deposition of carbon irrespective of ifthere is some Ti available for forming TiC or not. Consequently, the de-posited film composition will change from Ti to TiC to pure carbon as thesupply of the reactive hydrocarbon gas increases. The carbon concentra-tion “c” in the film may thus vary as 0 < c < 100%. The film compositionwill not saturate at stoichiometric TiC as the supply of the reactive gasreaches high values. We have therefore chosen to call such processes non-saturated reactive sputtering processes. Here we will present a quite simplemodel describing the behavior of such non-saturated reactive sputteringprocesses. The results from the model point out that there will always besome free non-reacted carbon in the deposited films. It should be pointedout that the original “Berg-model” for reactive sputtering processes can-not be applied to non-saturated reactive sputtering processes. This is whywe present this new model.

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Oral presentations

A low deposition rate in poisoned mode: a triviality?

R. Schelfhout1, K. Strijckmans1, D. Depla1

1 Department of Solid State Sciences, Ghent University, Krijgslaan 281 (S1), 9000Gent, Belgium

Reactive DC magnetron sputtering (R-DCMS) operated at standard con-ditions is characterized by clear hysteresis effects, accompanied by a pro-nounced drop in deposition rate. Both effects are attributed to the lowsputtering yield value in the poisoned mode. Despite the scarce literaturedata on oxide sputtering yield measurements during R-DMCS, the occur-rence of a low sputtering yield is generally accepted and is considered tobe common knowledge. Numerous literature studies on argon ion beamoxide sputtering report however oxide sputtering yield values comparableto or even exceeding the sputtering yield of the pure metal. As such, astrong discrepancy in oxide sputtering yields during R-DCMS and argonion beam experiments appears to exist, which will be addressed from anexperimental point of view.

The experimental method of reactive gas consumption [1] offers a pathwayto rapidly measure the sputtering yield in the poisoned mode during R-DCMS and therefore allows to perform systematic sputtering yield studies.We will present oxide sputtering yield measurements of 13 different metalsas a function of the oxygen concentration in the discharge. These results,combined with in-vacuo XPS analysis of the target stoichiometry sheds anew light on the discrepancy between argon ion beam and R-DCMS exper-iments. The difference appears to be of a fundamental nature inherent tothe poisoned mode during R-DCMS. Although the oxygen concentrationin this mode is generally lower than 15%, this rather small oxygen concen-tration drastically impacts the target oxidation state and the overall sput-tering mechanism. The altering of the target state and consequently theoxide sputtering yield by oxygen implantation, strongly resembles oxygenion beam experiments known as Ion Beam Oxidation (IBO). The analogypermits to partially explain the low sputtering yield value during R-DCMS,but does not cover the entire story. As will be demonstrated, a peculiarrole is ascribed to the current density. This quantity differentiates DCMSfrom ion beam sputtering and can either enhance the lowering of the sput-tering yield or counteract this effect. The understanding of the influenceof the current density has therefore as well some practical implications.

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In addition, some attention will be given on experimental operation modesthat successfully reduce the lowering of the sputtering yield or alterna-tively, increase the deposition rate during magnetron sputter deposition.

[1] Schelfhout, R., K. Strijckmans, and D. Depla, Anomalous effects in the aluminumoxide sputtering yield. J. Phys. D: Appl. Phys. 51(2018) 155202

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Hybrid reactive deposition of W-C:H coatings by DCand High Power Impulse Magnetron Sputtering

F. Lofaj1, M. Kabatova1, J. Dobrovodsky2

1 Institute of Materials Research of the Slovak Academy of Sciences, Watsonova47, 040 01 Kosice, Slovakia

2 Advanced Technologies Research Institute, Faculty of Materials Science andTechnology in Trnava, Slovak University of Technology in Bratislava, J. Bottu25, 91724 Trnava, Slovakia

Reactive sputtering with hydrocarbon gasses for the deposition of hydro-genated a-C:H and W-C:H coatings exhibits several specific features re-lated to hydrocarbon decomposition that a term “hybrid PVD/PECVDsputtering”” is used for its description. This work is devoted to the inves-tigation of the effects of acetylene and hydrogen additions on the plasmacomposition and structure and chemical composition of W-C:H coatingsprepared by High Power Impulse Magnetron Sputtering in comparisonwith the conventional DC magnetron sputtering. The concentrations ofcarbon and hydrogen in the studied coatings were measured by Ruther-ford Backscattering (RBS) and Elastic Recoil Detection Analysis (ERDA)methods and correlated with their density, structure, phase compositionand hardness. The obtained results were analysed and the main differencesin the possible growth mechanisms between DCMS and HiPIMS were dis-cussed within the Jacob/von Keudell model.

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Oral presentations

High-rate reactive high-power impulse magnetronsputtering of In-Ga-Zn-O and ZnO:Al thin films atlow substrate temperature

J.Rezek1, J. Houska1, M. Prochazka1, P. Novak2, A.D. Pajdarova1

1 Department of Physics and NTIS, European Centre of Excellence, University ofWest Bohemia, Univerzitni 8, 30614 Plzen, Czech Republic

2 New Technologies – Research Centre, University of West Bohemia, Univerzitni8, 306 14 Plzen, Czech Republic

High-power impulse magnetron sputtering (HiPIMS) is a very suitableand progressive method for preparing high-quality oxide layers. Enhancedenergy of target material ions impacted onto the growing film could substi-tute thermal heating of the substrate which is very important in the caseof deposition on a heat sensitive substrates. In spite of this fact, the use ofreactive HiPIMS for the preparation of In-Ga-Zn-O (IGZO) and Al-dopedZnO (AZO) layers has been rarely reported only. In this paper we showthe use of reactive HiPIMS is an effective way to produce IGZO and AZOlayers, and that the value of pulse-averaged target power density beingup to 1020 W.cm-2 is a suitable parameter for controlling the optical andelectrical properties of the films. Optical emission spectroscopy (OES) ofthe plasma discharge was also carried out. OES shows the qualitativelychanges in particles fluxes composition to the substrate under differentpulse-averaged target power densities.

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Evolution of ion flux composition in reactive HiPIMSof zirconium oxide under peak current regulation bypulse frequency control

T. Shimizu1, S. Adzhani1, S. Ikeda1, M. Yang1, N. Britun2,S. Konstantinidis2

1 Division of Intelligent Mechanical Systems, Graduate School of System Design,Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, 191-0065, Tokyo, Japan

2 Chimie des Interactions Plasma-Surface, Universite de Mons, Mons, Belgium,Avenue Nicolas Copernic 1, Bat Materia Nova, 7000, Mons, Belgium

Stabilization of high temperature cubic phases of zirconia at room temper-ature without any doping of yttria has been an intense research interestto achieve high functional zirconia coatings for broad range of applica-tions. In particular, it is known that the oxygen vacancies in the zirconialattice are the sole responsible parameter for the stabilization [1]. As anapproach to synthesize the understoichiometric zirconia films, the presentstudy applied the process stabilization method for reactive HiPIMS bypeak current regulation using feedback control of pulse frequency [2]. Tostudy its feasibility in controlling the concentration of oxygen vacancies inreactive HiPIMS of Zr in Ar/O2 atmosphere, simultaneous measurementsof oxygen partial pressure with ion mass spectrometry were performed bycomparing with a conventional reactive gas flow control. As results, oxy-gen partial pressure was successfully varied by adjusting the pulse peakcurrent controlled with the pulse frequency even at a constant O2 flow.Furthermore, the evolution of the ion flux composition as a function ofregulated pulse frequency showed a similar trend as O2 flow control, show-ing the significant increase of flux of positive atomic oxygen ions as thereactive mode moved from the metallic mode to the transition mode, andfinally into the compound mode. Those similarities in ion flux compositionwith the conventional O2 flow control will indicate the possibility in precisecontrol of O vacancy contents in zirconia thin films by using peak currentregulation.

[1] Raza M, Scripta Materialia, 124 (2016), 26[2] Shimizu T, J Phys D Appl Phys., 49-6, (2016), 65202

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Oral presentations

Enhancement of film properties by controlling the ionenergy distribution using Bipolar HiPIMS

R.P. Viloan1, J. Gu2, R. Boyd1, U. Helmersson1

1 Plasma & Coatings Physics Division, IFM Materials Physics, Linkoping Univer-sity, Linkoping, SE-581 83, Sweden

2 School of Mechanical Engineering and Automation, Beihang University, Beijing,P.R. China

Controlling the ion energy distribution (IED) of ions in a highly ionizedplasma has a direct effect on the properties of the deposited thin film. Inthe case of High Power Impulse Magnetron Sputtering (HiPIMS) wherethe discharge is dominated by ionized metal species, the effect of tuningthe IED cannot be underestimated. As a usual case, the energy of incom-ing ions are controlled and are thus modified using a substrate bias, which,in cases where the substrates are non-conducting becomes challenging. Asolution to this is the application of a positive pulse (U+) following aregular HiPIMS pulse (U-), which here we call Bipolar HiPIMS, to in-duce ion acceleration to higher ion energies. In this study the effect of a200 µs positive pulse following a regular 30 µs negative HIPIMS pulse isinvestigated for sputter deposition of Ti in an Ar/N2 environment. Time-averaged ion mass spectroscopy measurements show that a portion of theion population are accelerated to the same energy as U+ and thermalizedions are decreased as U+ is increased. X-ray diffraction measurements onthe deposited TiN films reveal that compressive stress increases from ∼-2.0GPa to ∼-4.6 GPa as U+ is increased while the crystallography does notchange. Nanoindentation measurements also reveal an enhanced hardnessfrom ∼24 GPa to ∼4 GPa as U+ is varied from 0 V to 150 V, respectivelywhile electron microscopy show further densification of films when usingbipolar HiPIMS.

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Oral presentations

Reactive HIPIMS: Controlling stoichiometry andionization

H. Gerdes1, J. Rieke2, R. Bandorf1, T. Schutte3, G. Brauer1,2

1 Fraunhofer IST2 Institute for Surface Technology IOT TU-Braunschweig3 Plasus GmbH

In recent years, High Power Impulse Magnetron Sputtering (HIPIMS) hasshifted not only in research from metallic to reactive processes. For mid-frequency or DC processes, it is well known that for controlling the stoi-chiometry of the deposited films especially for oxides a process control isnecessary. This process control can be based on the target voltage, par-tial pressure, or plasma emission. While the target voltage is an averagedvalue over the target length, the other two can deliver values at differentlocation of the target. Therefore, the partial pressure and plasma emissioncan be used to control reactive processes over longer targets. However, bychanging the working point of a sputtering process, especially in HIPIMS,the peak current and therefore the film properties are changed.

This presentation will show a process control based on plasma emissionmonitoring, including a possibility to monitor the peak current in real-time. The process control allows on one hand to control the stoichiometryof the films and on the other hand the ionization degree of the sputteredmaterial.

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Oral presentations

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Posters

Posters

Towards Industrial Deposition of Metal Oxides forPassivating and Carrier Selective Contacts: MoOxDeposited by Industrial Size Reactive DC MagnetronSputtering and Industrial Size Linear EvaporationSource

V. Linss1, L. Tutsch2, M. Bivour2

1 Von Ardenne GmbH, Am Hahnweg 8, D-01328 Dresden, Germany2 Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstrasse 2, D-79110

Freiburg, Germany

Passivating contacts are considered as a possibility to enhance silicon basedPV performance due to lower interface recombination rates of charge car-riers. Most of the investigation on metal oxide based contacts so far wasdone in laboratory scale. Mass production requires the scale-up of the pro-cesses. This contribution reports on first deposition experiments of MoOxhole selective contacts by industrial size reactive magnetron sputtering andthermal evaporation. Reactive sputtering was carried out on a vertical in-line tool equipped with a rotatable target of 1 m length. Thermal evapora-tion was conducted with a linear evaporation source of 46 cm length. Filmswere deposited on solar cell precursors in order to estimate charge carrierselectivity and band bending induced into the c-Si wafer by the MoOxbased hole contact. First results show that the selectivity, band bending,and optical transmission of reactively sputtered MoOx films depend on theworking point of the reactive sputter process. However, the selectivity stillis far from what was reached in small-scale evaporation experiments. Filmsdeposited with the industrial linear evaporation source show much betterselective properties even comparable to lab-scale evaporation. Based onthese results there seems to be a high potential to transfer the small scalelaboratory evaporation process to larger areas in dynamic deposition, butfurther work is needed to tailor the properties of the sputter depositedMoOx.

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Posters

Diagnostics of magnetron target cleaning process bylaser-based spectroscopy

N. Britun1, R. Schelfhout2, D. Depla2

1 Chimie des Interactions Plasma-Surface (ChIPS), University of Mons, Place duParc 23, 7000 Mons, Belgium

2 Research Group DRAFT, Ghent University, Department of Solid State Sciences,Krijgslaan 281/S1, 9000 Ghent, Belgium

Time-resolved processes related to magnetron target poisoning and clean-ing are among the least studied ones in reactive magnetron sputtering.This is related to the fact that the direct time-resolved measurement ofthe oxide layer formation on (or removal from) the target surface is a verychallenging task. So far it is known that the oxide layer thickness is onlya few nanometers and the typical time to sputter out this layer is on theorder of hundreds of milliseconds up to a second [1-3]. Short cleaning timeand low layer thickness hinder systematic studies of the target poisoningand cleaning dynamics. A spectroscopic analysis of the plasma adjacent tothe target can offer alternative pathways to investigate reactive sputteringprocesses during the target cleaning by sputtering. This is in particular re-lated to the laser-based spectroscopy which possesses excellent time- andspace- resolution and a rather good sensitivity to the plasma-producedspecies.

This work is focused on studying the target sputter cleaning process bydetecting O ground state atoms near the target surface, as a result of thesputter removal of the O-compounds from a Ti target. An experimentalprocedure for the time-resolved detection of O atoms produced during thetarget surface cleaning is proposed and implemented, in which both directcurrent magnetron sputtering (DCMS) and high-power impulse magnetronsputtering (HiPIMS) discharges were used for target cleaning. A dedi-cated discharge synchronization scheme assuring a fixed target poisoning-cleaning cycle ( 100 s), combined with triggered O atom detection has beendeveloped for this purpose. The ground state O atoms were externally ex-cited by a pulsed dye laser, following by detection of the fluorescence lightby a gated detector. The O number density in the discharge is obtainedby calibration [4].

The preliminary results clearly indicate the detectability of O atoms as aresult of sputter cleaning of a (poisoned) target surface. We found that us-

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ing HiPIMS for target cleaning, the produced O number density is roughlyone order of magnitude higher than that obtained in the DCMS case. Atthe same time, based on the time evolution of the discharge current, thetransition to metallic mode in the HiPIMS case takes about 30 sec, whereasin the DCMS case this time is much shorter, which is likely related to lowertarget sputtering rate in the first case. A concept of an improved exper-imental setup using HiPIMS discharge with a synchronized ignition hasbeen proposed for the future measurements.

[1] Depla, D., J. Haemers, and R. De Gryse. Thin Solid Films, 2006. 515: 4[2] Schelfhout, R., et al., Applied Surface Science, 2015. 355: 5[3] Kubart, T. and A. Aijaz. Journal of Applied Physics, 2017. 121: 9[4] Britun, N., et al. J. Phys. D: Appl. Phys., 2017. 50: 075204

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Synthesis and Characterization of (Ti, Mg)N ThinFilms

M. A. Gharavi1, A. le Febvrier1, B. Alling1, R. Armiento1

and P. Eklund1

1 Thin Film Physics Division, Department of Physics, Chemistry, and Biology(IFM), Linkoping University, SE-58183 Linkoping, Sweden

Scandium nitride has recently gained interest as a prospective compoundfor thermoelectric applications due to its high Seebeck coefficient [1]. How-ever, ScN also has a relatively high thermal conductivity, which limits itsthermoelectric efficiency and figure of merit (zT). Theoretical studies haveshown [2,3] the possibility of synthesizing a ternary nitride that shares theelectronic structure features of ScN by replacing the group 3 element scan-dium with a group 2 alkaline earth and group 4 transition metal. Using zeroKelvin density functional theory (DFT) calculations, the phase stabilityand semiconducting properties of TiMgN2, ZrMgN2 and HfMgN2 com-pounds have been predicted. The stable compounds may have one of twocompeting crystal structures: a monoclinic structure (LiUN2 prototype)or a trigonal superstructure (NaCrS2 prototype; R3mH ). The predictedstability of these compounds suggest that they can be synthesized by, e.g.,physical vapour deposition [4].

In this study, we synthesized (Ti, Mg)N thin films by reactive dc mag-netron sputtering by alloying TiN with Mg according to a 1:1 metal atomratio. The thin films were deposited onto 0001 sapphire (Al2O3) substratesat 400 C under a 25 sccm/65 sccm N2/Ar gas flow, keeping the total gaspressure at 4.9 mTorr (0.65 Pa). Characterization by θ-2θ X-ray diffraction(XRD) and pole figure measurements shows rock-salt cubic (111) growthwith a twin domain structure. The films yield an electrical resistivity of 150mΩcm as measured by a 4-point-probe station for the 1:1 Ti/Mg atomicratio measured by energy dispersive X-rays (EDX). This is done by con-trolling the magnetron target power output. Scanning electron microscopy(SEM) shows a high degree of porosity in the film which could be dueto the relatively low deposition temperature and limited adatom surfacemobility. In addition, we aim to anneal the (Ti,Mg)N films in both atmo-spheric conditions and pure nitrogen in order to test both the oxidationresistance of the film and to study whether additional high temperature(∼1000 C) annealing in a nitrogen gas flow could lead to the formationof the NaCrS2 superstructure.

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[1] P. Eklund, S. Kerdsongpanya and B. Alling: J. Mater. Chem. C, (2016) 4, 3905 -3914

[2] M. A. Gharavi, R. Armiento, B. Alling and P. Eklund: J. Mater. Sci., (2018) 53,4294 – 4305

[3] Y. Irokawa and M. Usami: Jpn. J. Appl. Phys. (2016) 55, 098001[4] B. Wang, S. Kerdsongpanya, M. E. McGahay, E. Milosevic, P. Patsalas and Daniel

Gall: J. Vac. Sci. Technol. A, (2018) 36, 061501

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Control of the texture of gadolinia-doped ceria thinfilms in reactive magnetron sputtering

M. Mickan1, A. Caillard1, A.-L. Thomann1

1 GREMI (Groupe de Recherches sur l’Energetique des Milieux Ionises)UMR7344 CNRS/Universite d’Orleans, 14 rue d’Issoudun, 45067 Orleans, France

Gadolinia-doped ceria (GDC) is an oxygen ion conducting material thatcan be used as an electrolyte in solid oxide fuel cells (SOFC). GDC thinfilms are often used as Sr diffusion barriers in SOFC based on YSZ andLSCF. In this work, the deposition of GDC thin films by reactive DC mag-netron sputtering was investigated. First, the effect of the target-substratedistance and the position of the gas inlet on the critical point of the hys-teresis was assessed. Films were then deposited in the metallic mode andsubsequently oxidized by annealing in air or in oxygen. Under certain con-ditions the critical point in the hysteresis could be shifted to higher oxygenflow rates, which allowed the deposition of fully oxidized films in the metal-lic mode. Additionally, it was possible to control the preferential orienta-tion of the films by adjusting the target/substrate distance and the oxygenflow rate, and by applying an RF substrate bias. Finally, the influence ofdifferent annealing methods and temperatures on the film properties wastested, such as an annealing in air with a slow heating rate as well as arapid thermal annealing (RTA) in an oxygen atmosphere.

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Influence of gas composition used for ion cleaning stepon diffusion layer formation during S-phase coatingdeposition on austenitic stainless steel

S. Fryska1, J. Słowik1, J. Baranowska1

1 Institute of Materials Science and Engineering, Szczecin, Poland

During reactive magnetron sputtering of nitrogen expanded austenite coat-ing (S-phase) on austenitic stainless steel substrate the nitrogen diffusionfrom coating to the substrate is frequently observed. Forming of the dif-fusion layer under the S-phase coating could potentially improve adhesionand load bearing capacity of the coating–substrate system. The possibilityof diffusion layer appearance depends on deposition parameters: tempera-ture and nitrogen content in reactive atmosphere. Nevertheless, to initiatediffusion process it is necessary to remove passive layer of chromium oxidespresent on the substrate during ion cleaning step which usually is carriedout in argon DC or RF plasma. However, the process of oxides removal byphysical sputtering could be insufficient and the nitrogen diffusion layerobtained could be uneven and discontinuous. The use of atmospheres con-taining different gases is proposed to enhanced this process: argon (asreference), argon with hydrogen, argon with nitrogen, argon with ammo-nia and a mixture of all above. The following parameter were applied:temperature – 350 C, time – 30 min (for ion cleaning) and 60 min (forcoating deposition), two magnetron guns with austenitic stainless steel tar-get (type 304) with 500 mA dc current, RF bias 30 W (for ion cleaning)and 2 W (for coating deposition), gas pressure 20 mTorr (for ion cleaning)and 4 mTorr (for coating deposition). An effectiveness of ion cleaning stepwas evaluated by measurement of thickness, uniformity and continuity ofobtained nitrogen diffusion layers. The XRD and SEM techniques wereused to investigate the deposited coatings.

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Study of the Ni migration from sub-nanometric layerto thicker a zinc oxide layer

J. M. Voronkoff1, H. Montigaud1, S. Grachev1, T. Cretin2

1 Surface du Verre et Interfaces UMR 125 CNRS/Saint-Gobain, Aubervilliers,France

2 Saint-Gobain Recherche, Aubervilliers, France

Functional glazings for thermal isolation consist of stack of layers depositedby PVD magnetron sputtering on flat glass substrates at room tempera-ture. They combine metallic and dielectric thin layers in order to optimizereflectance in the infrared and transmission in the visible. For several appli-cations the final product (glass + layers) has to undergo post treatment athigh temperature (approx. 700 C). This step induces different phenomenawithin the stack such as inter layer diffusion, which are linked to the depo-sition process. For this study, we have focused our works on the behaviorof ultra-thin layers of nickel or NiCr (approx. 1 nm) in contact with a zincoxide dielectric layer (5-100 nm) during annealing treatment of several hun-dreds of C. Nickel migrates during such thermal treatments within ZnOlayer. The diffusion phenomena seem to be quite complex as the sputteringconditions influences the oxidation states and the microstructure of bothlayers NiCr and ZnO. In order to characterize the amplitude of Ni diffu-sion as best as possible, we developed a multi channels approach on modelstacks: Si wafer//SiN(10 nm)//NiCr(1 nm)//ZnO(100 nm). Ni diffusionwas monitored by Tof-SIMS characterization. Thanks to the analysis ofthe composition of ZnO surface during in situ heating (approx. 600C)combined with depth profiling of the whole stack, this approach highlightsdiffusion profiles and modes.

As mentioned before, the Ni diffusion depends on key parameters of NiCrlayer such as its oxidation states, its microstructure, and its thickness.XPS analyses were performed in order to estimate the oxidation statesand the morphology of the layer. These results were combined with AFMand electron microscopy (STEM-EDS) ones to refine the structural char-acterization. The influence of the early stages of ZnO deposition on thisthin NiCr layer was also studied.

Hence, the determination of the NiCr layer microstructure and chemicalstates using combined techniques gives insights on the parameters drivingthe macroscopic diffusion observed.

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In situ measurement setup to study thin film growthdeposited by reactive magnetron sputtering.

Q. Herault1, S. Grachev1, I. Gozhyk1, H. Montigaud1, R. Lazzari1

1 Laboratoire Surface du Verre et Interfaces, Saint-Gobain Recherche/CNRS, 39 quai Lucien Lefranc, Aubervilliers, 93303, France

2 Equipe Oxydes a basses dimensions, Institut des Nano Sciencesde Paris-Sorbonne Universite, 4 place Jussieu, Paris, 75252-Cedex 05, France

Reactive magnetron sputtering is a common technique of deposition atthe industrial scale. It involves complex phenomenon due to the variety ofspecies involved, such as electron, ions, neutral, etc. Consequently, depo-sition parameters are the keys to improve thin film quality. Among them,sample holder potential, deposition speed, deposition pressure, gas compo-sition, target-sample distance are generally identified as the most pertinent.

To understand the effect of these parameters, we developed different insitu measurements methods in the same chamber used during thin filmdeposition. Surface temperature, mechanical stress, optical reflectivity andresistivity measurement were chosen as complementary methods. Our insitu results, correlated to thin film morphology measured by ex situ mea-surements gave a good overview of the impact of deposition parameters ongrain size and deposition steps for example.

We propose here to describe this setup and results obtained in the case ofoxide layers deposited by reactive sputtering.

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Growth of nanoporous Ca3Co4O9 thin films preparedby reactive rf-magnetron sputtering followed by postannealing

B. Paul1, P. Eklund1

1 Thin Film Physics Division, Department of Physics, Chemistry, and Biology(IFM), Linkoping University, SE-581 83 Linkoping, Sweden

The misfit layered calcium cobalt oxide Ca3Co4O9 is considered among thebest of oxide thermoelectric materials for high temperature applications,because of its high Seebeck coefficient coupled with relatively high elec-trical conductivity. Ca3Co4O9 is often represented as [Ca2CoO3]xCoO2(x∼0.62) consists of alternative stack of rock-salt type Ca2CoO3 layer,serving as blocking layer for phonon, and CdI2-type CoO2 layer, serv-ing as conducting channel for charge carriers, along the c-axis. Tailor-ing of electronic and phononic properties via nanostructural tailoring insuch layered structure is quite challenging. Here, we report the growth ofhigh performance nanoporous Ca3Co4O9 thin films with controlled poros-ity by a simple and scalable sequential-sputtering-and-annealing method.Nanoporous films provide a new opportunity to tailor the phononic prop-erties by selective scattering of phonons, but without hampering the elec-tronic transport, leading to the enhancement of thermoelectric efficiency.Two step sputtering-annealing growth is performed by sequentially de-positing the multilayered CaO/CoO films on sapphire and mica substratesby rf-magnetron reactive sputtering from metallic targets of calcium andcobalt, followed by reactive annealing in oxygen atmosphere at 700 degreeCelsius. A three stage phase transformation from multilayered CaO/CoOfilms to the final phase of Ca3Co4O9 occurs during annealing. The ther-moelectric performance of the films is tunable with the controlled pores inthe films. Low electrical resistivity ∼ 7 mOhm.cm near room temperatureis obtained from the nanoporous films, resulting high power factor, 0.23mW.m-1K-2 near room temperature, which is comparable to the Ca3Co4O9thin films without porosity. Furthermore, these nanoporous films are read-ily to transferable to any arbitrary platform or substrate, due to the tai-lored weak adhesion between the films and the substrate by formation ofnanopillars in the interfacial region. With this transferability and the highpower factor near room temperature, the nanoporous Ca3Co4O9 films openavenues for low-temperature use of this material.

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Deposition of aluminum oxide coatings in a highcurrent magnetron discharge with millisecond scalepulses

A.V. Kaziev1, K.A. Leonova1, A.V. Tumarkin1, D.V. Kolodko1,2, D.G.Ageychenkov1, T.V. Stepanova1

1 National Research Nuclear University MEPhI (Moscow Engineering Physics In-stitute), 31 Kashirskoye Shosse, 115409 Moscow, Russia

2 Kotel’nikov Institute of Radio Engineering and Electronics, Fryazino Branch,Russian Academy of Sciences, 1 Vvedenskogo Sq, Fryazino, 141190 Moscow Re-gion, Russia

Transparent aluminum oxide coatings are extensively used in various ap-plications in electronics, mechanics, optics, etc. They exhibit outstandingmechanical properties, high resistance to abrasion and corrosion [1, 2]. Be-sides, their optical properties are attractive for enhancing optical power oflenses and producing reflection-type polarizers [3].The 200–1000 nm thick alumina coatings were deposited on glass samplesin a high-current impulse magnetron discharge (HCIMD [4, 5], or longHiPIMS). The aluminum target was sputtered in Ar/O2 gas mixture withdifferent flow ratios. Total pressure was 0.5 Pa, or 1.0 Pa. The pulse dura-tion was varied from 3 to 20 ms, with different duty factors. Both peak andaverage cycle power were changed in order to determine the most appropri-ate sputtering conditions. The refractive index and extinction coefficientwere measured and compared for different power management strategiesused.The reported study was funded by RFBR according to the research projectno. 18-38-20185/18.

[1] E. Dorre, H. Hubner, Alumina: Processing, Properties and Applications, Springer-Verlag, Berlin, 1984

[2] A. Wiatrowski, S. Patela, P. Kunicki, W. Posadowski, Vacuum 134 (2016) 54–62[3] G. Hass, M. H. Francombe, J. L. Vossen, Physics of Thin Films: Advances in Re-

search and Development, Academic Press, New-York, 1982[4] D. V. Mozgrin, I. K. Fetisov, G. V. Khodachenko, Plasma Phys. Rep. 21 (1995)

400–409[5] I. A. Shchelkanov, G. V. Khodachenko, High current impulse magnetron discharge.

Influence of the single pulse power on a deposition rate, Proc. 537th WE-Heraeus-Seminar Physics of Ionized and Ion-Assisted PVD: Principles and Current Trends,Dresden, Germany, 2013, p. 77

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Can we use the Normalized Energy Flux to control themicrostructure of reactively sputtered titaniumdioxide thin films?

P.-A. Cormier1, R. Tonneau2, P. Moskovkin2, S. Lucas2, S. Konstantinidis1

1 Plasma-Surface Interaction Chemistry (ChIPS), University of Mons, Place duparc 20, 7000 Mons, Belgium

2 Laboratoire d’Analyse par Reaction Nucleaire (LARN), Namur Institute of Struc-tured Matter (NISM), University of Namur, Rue de Bruxelles 61, 5000 Namur,Belgium

In this study, we used the Normalized Energy Flux at the substrate (NEF)as a standardization parameter to compare various deposition experiments.The NEF is expressed in eV per condensing Ti atom (eV/at) and was calcu-lated by combining energy flux data (mW/cm2) and Rutherford Backscat-tering Spectroscopy results (Ti at./cm2). The NEF was calculated for vari-ous sputtering conditions, in two different vacuum chambers. Among otherdiscrepancies, one could note that one of the chambers was furnished witha circular magnetron sputtering target while the other one was equippedwith two sputter targets set in closed – field configuration.

Despite the discrepancies in the deposition experiments, similar values ofthe NEF could be obtained by varying the sputter power and the p×dvalues. The microstructure of the TiO2 films deposited for similar NEFvalues were found to be alike, as observed by Scanning Electron Microscopyand X-Ray Diffraction.

Atomistic kinetic Monte-Carlo simulations were performed using theNASCAM code and the film are found to become denser as the energysupplied increases.

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Characterization of the porosity of silicon nitride thinlayers deposited by reactive magnetron sputtering

H. Montigaud1, T. Barres2, O. Stephan3, B. Tribollet4

1 Surface du Verre et Interfaces UMR 125 CNRS/Saint-Gobain, Aubervilliers,France

2 Saint-Gobain Recherche, Aubervilliers, France3 Laboratoire de Physique des Solides UMR 8502 CNRS/Universite Paris Sud,

France4 Laboratoire LISE UMR 8235 CNRS/Universite Paris VI UPMC, France

Functional glazing for many applications such as insulating windows pre-sent stack of thin layers deposited by PVD magnetron sputtering on flatglass substrates at room temperature. The low-emissivity property is main-ly obtained by a thin film of silver embedded between dielectric layers. Sil-icon nitride is commonly used for such layer in order to adjust optics andprotect silver during thermal post-treatment like tempering. The porosityof such thin films is thus a key parameter for the product durability andperformances [1].The nano-structural characterization of silicon nitride thin films was car-ried out by several microscopy techniques such as TEM, Scanning Trans-mission Electronic Microscopy in High Angle Annular Dark Field mode(STEM HAADF), and Electron Energy Loss Spectroscopy (EELS). Theporosity in SiNx layers was observed at the nanometer scale, and EELS/HAADF measurements gave access to the local composition in the thinfilm. The 3D morphology of the pores was evaluated combining observa-tions of the samples from different incidences (plane-view and cross sectionsobtained by means of FIB lamella). In parallel to the microscopic approach,we estimated the layer porosity at a larger scale by using Electrochemi-cal Impedance Spectroscopy (EIS). Impedance measurements have a highsensitivity to the pore distribution in the layer [2], providing a comple-mentary point of view on the layer morphological characteristics obtainedfrom STEM. The evolution of the layer nanostructure was studied usingthis double approach as a function of the SiNx deposition parameters suchas the duration (layer thickness), deposition pressure.

[1] J. Kulszyk-malecka, Diffusion studies in toughenable Low-E coatings, Phd thesis(2012)

[2] A. Perrotta, S. J. Garcia, J. J. Michels, A-M. Andringa, M. Creatore, ACS Appl.Mater. Interfaces, (2015) 7 (29), pp 15968–15977

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Reactive sputtered TiO2 thin film with highly controlover crystalline structure for photocatalytic H2evolution

S.Hejazi1, S. Mohajernia1, M. Licklederer1, P. Schmuki1,2

1 Department of Materials Science and Engineering WW4-LKO, University ofErlangen-Nuremberg, Martensstrasse-7, Erlangen D-91058, Germany

2 Chemistry Department, Faculty of Sciences, King Abdulaziz University, 80203,Jeddah, Saudi Arabia

Structurally and electrochemically tuned titanium oxide (TiO2) compactfilms have potential application as photocatalysts for H2 generation. Inthe present work TiO2 thin films were prepared by two methods, i) con-ventional anodic oxidation and ii) RF Magnetron Sputtering. The twolayers can be varied and are evaluated based on physical and chemicalproperties such as crystalline structure, conductivity and chemical com-position. The key target of such layers is their optimized performance foropen circuit hydrogen evolution. The results show that the sputtered lay-ers provide a mixture of of anatase and rutile crystalline structures. Thecrystalline structure for sputtered layer can be fully adjusted by the de-position temperature. The optimized sputtered layer TiO2 films show atenfold-enhanced open circuit H2 evolution in comparison to anodic lay-ers. The superior properties of sputtered film are explained by the controlover the crystalline structure (optimized ratio of rutile/anatase) and lowerrecombination of photo generated charge carriers due to a lower amountof trapping sites in such structures.

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The effect of pulse frequency under peak currentregulation in reactive HiPIMS of magnesium oxide

S. Adzhani1, H. Komiya1, Y. Teranishi2, M. Yang1, T. Shimizu1

1 Division of Intelligent Mechanical Systems, Graduate School of System Design,Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, 191-0065, Tokyo, Japan

2 Surface Coating and Chemical Technology Group, Tokyo Metropolitan IndustrialTechnology Research Institute (TIRI), 2-4-10 Aomi, Kohtoh-ku, 135-0064, Tokyo,Japan

Magnesium and its alloys as a biodegradable material have great potentialto be developed due to its excellent bio-compatibility and similar mechan-ical properties to natural bone. However, poor corrosion resistance has tobe improved for the medical applications. In our previous study, corrosionprotective MgO films were successfully deposited by reactive high-powerimpulse magnetron sputtering (HiPIMS), using peak current (Ipk) regula-tion mode to realize the high-rate deposition stabilized at transition modein reactive process [1]. In this study, by tuning the pulse frequency from400 Hz to 1200 Hz under the Ipk regulation at the reactive conditionsof O2 and Ar gas mixtures, we investigated its effect on growth of MgOfilm on Si wafer substrates. The chemical composition, surface morphologyand crystal structure of the films were analyzed to correlate to the in-vitrocorrosion behaviors in Hanks’ balanced salt solution (HBSS). Additionalion mass spectrometry studies and thermal flux measurements were per-formed to correlate the difference in plasma chemistry and the thermalflux at the substrate between the different pulse frequency conditions. Asresults, the MgO films with stoichiometric composition were successfullydeposited with deposition rate of approximately 27 nm/min under the Ipkregulation. By changing the pulse frequency under Ipk regulation, the low-est crystallinity was shown at the lowest pulse frequency of 400 Hz, whichshowed the best corrosion performance between different pulse frequencies.The influence of the ion flux of the sputtered species and the thermal fluxon the film growth of MgO thin film was discussed.

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Optical and electrical properties of AZO coatingdeposited by reactive magnetron sputtering:application to c-Si thin film solar cells

J. Muller, P. Moskovkin1, S. Lucas1

1 University of Namur (PMR-LARN), rue de Bruxelles 61, B-5000 Namur, Belgium

Transparent conductive oxides (TCO) present a large range of applicationssuch as optoelectronic devices, especially transparent front-side contact forsolar cells. In this last case, aluminum doped zinc oxide (ZnO:Al or AZO)can be a good alternative to indium tin oxide (ITO).

AZO deposition by reactive magnetron sputtering [1] on crystalline sili-cone substrates has been simulated thanks to a kinetic Monte Carlo model[2]. For these simulations, metallic (Zn, Al), reactive (O) and neutral (Ar)fluxes can be defined individually, with their own angular and energy distri-butions. Moreover, in order to mimic large samples, the periodic-supercellmethod was used.

Electrical properties (effective resistivity, sheet resistance) of the simu-lated film were computed by the mean of a finite-element code. Opticalproperties (reflectance, transmittance, absorbance, effective optical index)were evaluated by using two methods: the first one is the Transfer-Matrixmethod coupled to different effective medium models (Maxwell-Garnettand/or Bruggeman). The second method is the ADE-FDTD [3] allowingto predict optical phenomena like light trapping. A special attention wasgiven to the influence of the AZO pattern and the aluminum concentrationon the electrical and optical efficiencies. To go further, a first estimation ofthe light absorption by the active layer was done in the case of a simplifiedsolar cell stack (AZO/c-Si active layer/Ag back reflector) for different c-Sithicknesses.

[1] K. Ellmer et al., Surf. Coat. Technol., 93 (1) (1997), pp. 21-26[2] R. Tonneau et al., J. Phys. D. Appl. Phys. 51 (2018) 195202[3] J. Muller et al., J. Opt. Soc. Am. A, Vol. 28, pp 868-878. (2011)

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Uniformity of reactively sputtered NbTiN formicrowave kinetic inductance detectors

D. Thoen1,2,3, W. Haalebos3, V. Murugesan3, J. Baselmans1,3, A. Endo12

1 Department of Electrical Engineering, Faculty of Mathematics and ComputerScience (EEMCS), Delft University of Technology, Delft 2628 CD, The Nether-lands

2 Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University ofTechnology, Delft 2628 CJ, The Netherlands

3 Netherlands Institute for Space Research (SRON), Utrecht 3584 CA, The Nether-lands

Superconducting niobium-titanium-nitride (NbTiN) films are widely usedfor submillimetre wave astronomy. Because of their large superconductinggap energy, high resistivity and high kinetic inductance, they are ideallysuited for large area, sensitive superconducting microwave kinetic induc-tance detectors (MKID). However, the uniformity in thickness and elec-tromagnetic properties of NbTiN thin films is a critical issue for upscal-ing MKID arrays. In particular, the resonance frequency scatter dF ofMKIDs are reducing the number of MKIDs that can be used for actualdetection purposes, with dF the difference in frequency between designfrequency Fdesign and the actual resonator frequency Fresonator. TypicalNbTiN MKID internal quality factors (Qi = Fresonator/FFWHM ) are upto several millions for Fresonator between 4 GHz - 8 GHz and the full widthhalf maximum (FWHM) frequency bandwidth FFWHM. The total numberof resonators that can be packed in frequency space, is thus limited bydF . For our ultimate goal we require dF to be lower than 0.006 MHz (ora fractional value of 2 × 10−6 for Q = 105. In this paper we show howthe calculated dF varies over a 100 mm diameter area for NbTiN filmssputtered in two different DC magnetron reactive sputtering systems. Onehas a circular target of 100 mm diameter, the other a rectangular target of12.0 mm× 444.5 mm, where we also performed depositions while shuttlingthe substrate in front of the target to increase film thickness uniformity.Input for the calculation are locally determined film properties: thickness,square resistance, resistivity and critical temperature. The derived valuesfor dF that we obtain, are several orders of magnitude larger than theultimate limit, so we have to take the local film properties into accountwhen designing the MKID-based detector arrays. Future work is focusingon direct measurement of dF in order to understand its origin and nature.

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The (in)stability of process control mechanisms inreactive DC sputtering deposition

K. Strijckmans1, R. Schelfhout1, D. Depla1

1 Department of Solid State Sciences, Ghent University, Krijgslaan 281(S1), 9000Gent, Belgium

The RSD model is currently the most advanced model to describe processcurves during reactive DC magnetron sputtering deposition. It tries to im-plement the most essential chemical and physical processes to understandthe most of the reactive sputtering process. The considered operation pa-rameters in the model are the reactive/inert gas flow, the pumping speed,the discharge current/voltage/power and the target/substrate geometry.Together with the material dependent parameters such as sputter yields,reaction coefficients, and secondary electron emission yields, they definethe outlook of the process curves and especially their intrinsic instabil-ity properties which may manifest in hysteresis behavior. Indeed the RSDmodel is now capable in simulating a more broader range of process curves.

Getting control on the process and handling the possible hysteresis is oneof the main concerns to obtain a desired thin film at an economical highdeposition speed. Removing the hysteresis to establish stable process con-trol is one way in obtaining these favorable deposition conditions. However,the approaches for hysteresis removal like increasing pumping speed/inertgas pressure or reducing target area, are either hard to establish or induceunfavorable working conditions. Another way is getting along with thehysteresis and access the unstable transition regime by feedback controlwhich may make the process control more complex. However, it has beenshown that this unstable transition regime can sometimes be operatedstable when a right choice of controlling parameter is made. Its successdepends basically on the material/reactive gas combination at hand and isprimarily defined by the mutual difference in secondary electron emissionyields of the metal and the formed compound. Such stabilization can forexample be obtain for the Al/O2 system while this is not the case for theTi/O2 system. Here the proposed solutions are investigated by the RSDmodel, with an emphasis on the origin why some material/reactive gassystems are intrinsic harder to control than others.

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Modelling reactive HiPIMS deposition with fixedaverage power and varying pulse frequency

T. Kozak1

1 Department of Physics and NTIS – European Centre of Excellence, Universityof West Bohemia Univerzitni 8, 306 14 Plzen, Czech Republic

Reactive high-power impulse magnetron sputtering (HiPIMS) is being usedto prepare various oxide, nitride of oxynitride films. It has been shown thatthe increased degree of ionization of sputtered atoms and of dissociation ofthe reactive gas is beneficial for film quality and film composition control.One of the methods we used to control the composition of films is by vary-ing the pulse frequency while keeping the pulse length, the average targetpower and the reactive gas partial pressure constant. As a consequence,the average target power in a pulse is varied. The actual composition ofthe target during the deposition is a results of several competing pro-cesses – mainly sputtering of the target (decreasing compound coverage)and chemisorption and implantation of reactive gas particles into the tar-get (increasing compound coverage). Also, the return of ionized sputteredatoms onto the target plays an important role by lowering the depositionflux of the sputtered material. With an increasing target power in a pulse,all these competing processes are enhanced and it is difficult to estimatethe resulting trends without detailed evaluation. We use a reactive HiP-IMS model [1] extended by a minimalistic discharge plasma model (forthe “ionization region” in front of the target) to study the trends in thetarget composition and deposition rate under these conditions. Especially,the effects of material parameters on the model results is studied.

[1] T. Kozak, J. Vlcek, A parametric model for reactive high-power impulse magnetronsputtering, J. Phys. D.: Appl. Phys. (2016) 49 055202

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Why not combine sputtering with a mini e-beam evaporator for sub-molecular coatings.

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Do you need high quality coatings?

Plasma Quest’s proprietary sputtering technology, High Target Utilisation Sputter-ing, HiTUS, enables the user to have independent control of the amount and energy of the sputtered material, greatly expanding process capability to produce new or enhanced performance coatings. HiTUS can provide: - Excellent material quality- High deposition rate with no loss of material properties (Potential for 10 – 100x improvement over conventional sputter rates)- Low Temperature of deposition (deposition onto polymer substrates )- Stoichiometry control- Crystallinity control- Improved efficiency

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Conference and technical exhibitionat the Fraunhofer IST in Braunschweig, Germanyhttp://2019.rsd-conference.eu

The 18th International Conference on Reactive Sputter DepositionDecember 5 – 6, 2019

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DaTe

Fraunhofer Institute for Surface Engineering and Thin Films IST Bienroder Weg 54 E, 38108 Braunschweig, Germany rsd@ist.fraunhofer.de

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