Springer Series in Surface Sciences 64 Olaf Stenzel Miloslav Ohlídal Editors Optical Characterization of Thin Solid Films Springer Series in Surface Sciences Volume 64 Series editors Roberto Car, Princeton University, Princeton, NJ, USA Gerhard Ertl, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany Hans-Joachim Freund, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany Hans Lüth, Peter Grünberg Institute, Forschungszentrum Jülich GmbH, Jülich, Germany Mario Agostino Rocca, Dipartimento di Fisica, Università degli Studi di Genova, Genova, Italy This series covers the whole spectrum of surface sciences, including structure and dynamicsofcleanandadsorbate-coveredsurfaces,thinfilms,basicsurfaceeffects, analytical methods and also the physics and chemistry of interfaces. Written by leading researchers in the field, the books are intended primarily for researchers in academia and industry and for graduate students. More information about this series at http://www.springer.com/series/409 í Olaf Stenzel Miloslav Ohl dal (cid:129) Editors Optical Characterization of Thin Solid Films 123 Editors OlafStenzel MiloslavOhlídal Abbe Schoolof Photonics Institute of Physical Engineering Friedrich-Schiller-University Jena BrnoUniversity ofTechnology Jena, Thüringen Brno Germany Czech Republic and Fraunhofer Institut für AngewandteOptik undFeinmechanik IOF Jena Germany ISSN 0931-5195 ISSN 2198-4743 (electronic) SpringerSeries inSurface Sciences ISBN978-3-319-75324-9 ISBN978-3-319-75325-6 (eBook) https://doi.org/10.1007/978-3-319-75325-6 LibraryofCongressControlNumber:2018931163 ©SpringerInternationalPublishingAG2018 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. 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Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland Fluorite Crystal Detail of a painting by Vera Andrianova Forwerk, a Bulgarian master student of photonics at Abbe School of Photonics, Friedrich Schiller University Jena, Germany. Printed with permission. Fluorite is a naturally occurring crystalline modification of calcium fluoride, a widely used optical material for applications as windows, lenses and thelike from the middle infrared up to the vacuum ultraviolet spectral regions. See Sect. 8.2.2 for optical constants. Foreword Thepresentbookprovidesthereaderwithtop-notchreportsfromtheworkbenches of renowned colleagues in the field of thin film characterization. The field of thin films is an ever-expanding area with optical coatings repre- senting the oldest, yet perhaps the fastest, still developing area among the various, multidisciplinary applications of thin films. Amostcurrentsnapshotofthevastexpanseandspeedbywhichthefieldofthin films is moving is provided in this book. Thin films are abundant in modern science and engineering owing to sophisti- cated and continuously improved techniques for their preparation, their usefulness in basic and applied research, and their suitability for mass production in a sheer limitless variety of new and advancing device structures. Perhaps one of the most intriguing peculiarities of thin films is inscribed within their optical properties, whichdependinmostcomplexwaysonthestructuralarrangementsofmatterfrom atomic to macroscopic scales. Theauthorsinthisbookprovidethereaderwithasetofchapterstogainafast foothold in understanding of the topics needed to engage in optical thin film characterization at the present level of the state of the art. Theelectromagneticspectrumoffersabroadestintervaloverwhichtheresponse of thin films can be interrogated. Advanced optical and structural investigations techniques are required for characterization of thin films. Likewise, intricate theo- reticaltoolsareneededwhentheattemptismadetorelatetheobservationsmadeto therealstructureofthethinfilms.Thetoolsforcalculationsdescentfromquantum mechanicsaswellascontinuumphysicsconcepts,andtheirimplementationscanbe made easily on personal computers or may reach the limits of contemporary computation capabilities. The book reflects the complexity of this topic from a multitude of perspectives. Introductory portions provide the reader with the information on techniques for opticalandstructural characterization ofadvanced opticalthin films.Examples are presentedwherethereaderiswalkedthroughthecomplexityandchallengeswhich one faces when simply questions are related to complex structured real samples. Rather than attempting to cover the vastness of all possible situations, the book vii viii Foreword focusesonselectedexamples,suchasmicrostructuregradients,porosity,damages, defects, thin films composed of regular nano- and microstructures, and challenges in instrumentation and their circumvention. Thebookisnotthefirstinthisfieldandwillnotbethelast.Itisthecurrentbest step stone to the next level of understanding. I found the book a very interesting read and recommend it highly to beginners andexpertsalike,bothinthefieldofopticalcharacterizationofthinfilmsaswellas toanyoneinourexpanding,multidisciplinaryscientificcommunitywhoisworking with thin films. Lincoln, NE, USA Mathias Schubert July 2017 Preface TheideaforthisbookaroseatabilateralworkshopheldbycolleaguesfromCzech Republic and Germany on optical coating characterization in Brno, Czech Republic, October 11–13, 2016. The workshop dealt with different aspects of thin film optical characterization, including modeling, spectrophotometric approaches, spectroellipsometric approaches, specifics of characterization of defected or cor- rugated coatings, as well as the measurement of smallest optical losses with laser-basedexperimentalequipment.Itthusprovidedasnapshotonthecurrentstate of the art in diverse branches of optical coating characterization. In a narrower sense, all speakers at the workshop stemmed from research facilitieslocatedeitherinBrno(CzechRepublic)orinJena(Germany),sothatthe broad circle of characterization approaches presented there also served as a demonstration of the analytic possibilities located in these two cities. We strongly believe that the material discussed and presented at the workshop maybeofinteresttoabroaderaudience.Therefore,eachofthespeakerswasaskedto extendthecontentofhisorherpresentationinordertosupplyachapterthatbecame partofthepresentbook.Itwasourfirstintentiontoprovideaguidetomodernand powerful thin film characterization techniques while emphasizing the benefits of their coherent interaction, even when including non-optical techniques into the characterization approach. Thus, atomic force microscopy combined with mea- surementsoftheelasticallyscatteredlightappearstobeapowerfultoolforsurface andfilmroughnessinvestigation.Informationonfilmporositymaybegainedfrom simple spectrophotometric (or spectroellipsometric) measurements performed in different ambient conditions and spectral ranges, combined with an elemental analysisperformed,forexample,byenergy-dispersiveX-rayspectroscopy. Our second intention was to emphasize the role of modeling. Practically throughout the whole book text, emphasis is placed on the development and pre- sentationofmanageabletheoreticalmodelswithhighestpredictivepower,andwith clearly defined interfaces to interact with experimentally available input data. All presented models are applicable to broadest classes of characterization problems currently needed in industrial and partially also in academic research. In this con- text, characterization examples are presented, which are in most cases of high ix x Preface practical relevance today. They stem from real characterization problems and illustrate the feasibility of the coherent interaction of robust theoretical approaches and modern commercially available measurement facilities. Concerningthetargetaudienceofthisbook,itisourfeelingthateveryscientist or engineer having finished a master study in a physical, chemical, or engineering discipline and being involved in thin film characterization tasks can benefit from reading this book. The editors are extremely grateful to all authors for their effort to provide high-qualitycontributionsinaveryshorttime—ittooklessthanninemonthsofthe workshop to the submittal of the book manuscript. Many thanks are also to Professor Mathias Schubert, Electrical & Computer Engineering, University of Nebraska–Lincoln, for critical remarks to the manuscript and, in particular, for contributing a foreword to this book. AllGermanauthorsacknowledgethefinancialsupporttotheworkshopprovided by the Deutsche Forschungsgemeinschaft DFG. All authors thank to the Brno University of Technology and Masaryk University, Brno, for organizing the workshop. Jena, Germany Olaf Stenzel Brno, Czech Republic Miloslav Ohlídal