Glancing Angle Deposition of Thin Films

Dr Matthew M. Hawkeye is a postdoc at University of Alberta who earned his Ph.D. in electrical engineering working with the Brett group on GLAD technology and who has worked on the GLAD technique since 2004. From 2010-2012, he worked as a postdoc at the University of Cambridge, during which time he authored numerous articles on nanoscale photonics and contributed to a BBC Horizon series special on synthetic biology. His publications include a review article in Journal of Vacuum Science and Technology A on the GLAD technique which has more than 200 citations to date.Dr Michael T. Taschuk received his Ph.D. degree in electrical engineering from the University of Alberta in 2006 for his work developing the laser-induced breakdown spectroscopy technique. He has been working as a research associate at Alberta on GLAD since 2007, studying optical and sensor applications of GLAD thin films. He has published 33 peer-reviewed papers on the GLAD technique, as well as a book chapter covering GLAD theory and applications.Dr Michael J. Brett is Canada Research Chair at the Department of Electrical and Computer Engineering at the University of Alberta, where he has taught since 1986. He also holds an appointment as Program Coordinator (Energy) at the National Institute for Nanotechnology. After commercialization success and worldwide sales of his microelectronics simulation software SIMBAD, his group developed and popularized the GLAD process in 1994, and their research has focused on this technique since that time, leading to over 190 journal papers and 5 patents that deal with GLAD and its applications.  He is also the author of 4 book chapters and the acknowledged field leader in GLAD research.

• Series Preface xiPreface xiii1 Introduction: Glancing Angle Deposition Technology 11.1 Nanoscale engineering and glancing angle deposition 11.2 GLAD-vantages 41.2.1 Nanoscale morphology control 41.2.2 Broad material compatibility 61.2.3 Novel thin-film material properties 101.2.4 Compatibility with standard microfabrication processes 101.2.5 Scalable fabrication method 111.3 The roots of glancing angle deposition: oblique deposition 121.4 The importance of experimental calibration 131.5 Computer simulations of glancing angle deposition growth 151.6 Major application areas in glancing angle deposition technology 171.6.1 Energy and catalysis 171.6.2 Sensing applications 191.6.3 Optics 201.7 Summary and outline of the book 212 Engineering Film Microstructure with Glancing Angle Deposition 312.1 Introduction 312.2 Basics of conventional film growth 322.2.1 Physical vapour deposition 322.2.2 Nucleation and coalescence 332.2.3 Column microstructure 352.3 Glancing angle deposition technology: microstructural control via substrate motion 372.4 Engineering film morphology with α 412.4.1 Controlling microstructure and porosity 412.4.2 Directional column growth: column tilt β 442.5 Engineering film morphology: column steering via φ rotation 472.5.1 Controlling column architecture with φ: helical columns 472.5.2 Controlling microstructure with rotation speed: vertical columns 482.5.3 Continuous versus discrete substrate rotation 492.6 Growth characteristics of glancing angle deposition technology films 532.6.1 Evolutionary column growth 532.6.2 Column broadening 562.6.3 Column bifurcation 572.6.4 Anisotropic shadowing and column fanning 592.7 Advanced column steering algorithms 602.7.1 β variations in zigzag microstructures 612.7.2 Spin–pause/two-phase substrate rotation: decoupling β and film density 632.7.3 Phisweep motion: competition-resilient structure growth 672.8 Additional control over film growth and structure 722.8.1 High-temperature glancing angle deposition growth 722.8.2 Multimaterial structures: co-deposition processes 753 Creating High-Uniformity Nanostructure Arrays 813.1 Introduction 813.2 Seed layer design 823.2.1 Seed spacing and seed height 843.2.2 Seed lattice geometry 863.2.3 Seed size 873.2.4 Planar fill fraction 893.2.5 Seed shape 903.2.6 Two-dimensional shadow coverage 913.2.7 Seed material 943.2.8 Design parameter summary 953.3 Seed fabrication 953.3.1 Conventional techniques 963.3.2 Unconventional techniques 973.4 Advanced control of local shadowing environment 993.4.1 Preventing bifurcation: slow-corner motion 993.4.2 Preventing broadening: phisweep and substrate swing 1024 Properties and Characterization Methods 1134.1 Introduction 1134.2 Structural analysis with electron microscopy 1134.2.1 Practical aspects 1144.2.2 Scanning electron microscope image analysis 1174.2.3 Three-dimensional column imaging: tomographic sectioning 1224.2.4 Characterizing internal column structure with transmission electron microscope imaging 1244.3 Structural properties of glancing angle deposition films 1264.3.1 Film surface roughness and evolution 1264.3.2 Column broadening 1284.3.3 Intercolumn spacing and column density 1334.4 Film density 1344.4.1 Controlling density with α: theoretical models 1354.4.2 Experimental measurement and control of film density 1364.5 Porosimetry and surface area determination 1404.5.1 Surface area enhancement in glancing angle deposition films 1414.5.2 The pore structure of glancing angle deposition films 1444.6 Crystallographic texture and evolution 1464.7 Electrical properties 1484.7.1 Resistivity in microstructured glancing angle deposition films 1484.7.2 Anisotropic resistivity 1514.7.3 Modelling glancing angle deposition film resistivity 1534.7.4 Individual nanocolumn properties 1544.8 Mechanical properties 1554.8.1 α effects on film stress 1554.8.2 Hardness properties 1584.8.3 Elastic behaviour of glancing angle deposition films 1594.8.4 Additional mechanical properties 1635 Glancing Angle Deposition Optical Films 1735.1 Introduction 1735.2 The optics of structured glancing angle deposition films 1735.2.1 Optical anisotropy in columnar glancing angle deposition films 1735.2.2 Modelling glancing angle deposition films with effective medium theory 1765.2.3 The column and void material refractive indices 1795.2.4 Modelling form birefringence via the depolarization factor 1805.2.5 Dealing with microstructural uncertainty: bounds on the effective dielectric function 1825.3 Calibrating optical properties of glancing angle deposition films 1825.3.1 Basic measurements: isotropic approximations 1835.3.2 Calibrating anisotropy with polarization-sensitive measurements 1855.3.3 In-depth characterization with generalized techniques 1865.3.4 Additional factors 1865.4 Controlling glancing angle deposition film optical properties 1875.4.1 Basic refractive index engineering with α 1875.4.2 Controlling planar birefringence with α 1885.4.3 Optimizing birefringence with serial bideposition 1895.4.4 Modulating birefringence with complex φ motions 1925.4.5 Controlling n with advanced glancing angle deposition motions 1955.5 Graded-index coatings: design and fabrication 1955.5.1 General design method for glancing angle deposition graded-index coatings 1965.5.2 Designing φ motions for high-accuracy graded-index coatings 1975.5.3 Specific examples 1995.5.4 Antireflection coatings 1995.5.5 Rugate interference filters 2015.5.6 Avoiding high- α growth instabilities in graded-index films 2055.6 Designing helical structures for circular polarization optics 2065.6.1 Optics of chiral glancing angle deposition media 2065.6.2 Engineering basic helical structures 2085.6.3 Polygonal helical structures 2105.6.4 Optimization of circular bragg phenomena with serial bideposition 2125.6.5 Microcavity design in helical structures 2135.6.6 Fabricating graded-birefringence thin-film designs 2145.7 Practical information and issues 2165.7.1 Post-deposition tuning 2165.7.2 Environmental sensitivity 2175.7.3 Optical scattering 2176 Post-Deposition Processing and Device Integration 2276.1 Introduction 2276.2 Post-deposition structural control 2276.2.1 Annealing 2276.2.2 Chemical composition control 2316.2.3 Microstructural control via chemical etching 2316.2.4 Ion-milling structural modification 2336.2.5 Column surface modifications 2356.3 Deposition onto nonplanar geometries 2366.4 Photolithographic patterning of glancing angle deposition thin films 2376.5 Encapsulation and replanarization of glancing angle deposition films 2406.5.1 Encapsulation layer substrate motions 2406.5.2 Film stress in encapsulation layers 2426.6 Integrating electrical contacts with glancing angle deposition microstructures 2446.6.1 Planar electrode configurations 2446.6.2 Parallel-plate electrode configurations 2456.7 Films in liquid environments 2476.8 Using glancing angle deposition microstructures as replication templates 2516.8.1 Single- and double-template fabrication processes 2516.8.2 Nanotube fabrication via template fabrication 2527 Glancing Angle Deposition Systems and Hardware 2617.1 Introduction 2617.2 Vacuum conditions 2617.2.1 Vacuum requirements for glancing angle deposition systems 2617.2.2 Physical vapour deposition process gases and higher pressure deposition 2637.3 Thickness calibration and deposition rate monitoring 2657.3.1 Source directionality and tooling factor 2657.3.2 Thickness calibration at nonzero α: deposition ratios 2677.3.3 Extended source: effect on collimation 2697.4 Uniformity calculations for glancing angle deposition processes 2707.4.1 Calculating geometry variation over a wafer 2707.4.2 Mapping out thickness variation 2727.4.3 Calculating parameter variations for moving substrates 2747.4.4 Calculating thickness uniformity for moving substrates 2767.4.5 Calculating column orientation uniformity 2787.5 Substrate motion hardware 2817.5.1 α motion accuracy and precision 2817.5.2 φ motion requirements 2837.5.3 Additional factors to consider 2847.5.4 Substrate heating and cooling approaches 2857.6 Scalability to manufacturing 286References 286A Selected Patents 289Index 297