Thin Films
This chapter provides an extended introduction to the basic principles of thin-film technology, including deposition processes, structure, and some optical and electrical properties relevant to this volume. The material is accessible to scientists and eng
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Thin Films
29. Thin Films
The earliest use of thin films by mankind is probably in the application of glazes to brickwork and pottery. Tin glazing was discovered by the Assyrians and was used to coat decorative brickwork. Glazed brick panels have been recovered from various archeological sites, with a fragment from Nimrud being dated to about 890 B.C. Various alternative types of glaze have since been developed, and are used both to overcome the effects of porosity in pottery and for decorative purposes. The importance of thin films in optics was first recognised in the 17th century by Hooke, Newton and others. In 1675
29.1 Deposition Methods ............................. 661 29.1.1 Physical Deposition Methods ...... 661 29.1.2 Chemical Deposition Methods ..... 677 29.2 Structure ............................................ 29.2.1 Crystallography ......................... 29.2.2 Film Structure ........................... 29.2.3 Morphology ..............................
682 682 683 688
29.3 Properties ........................................... 692 29.3.1 Optical Properties ...................... 692 29.3.2 Electrical Properties ................... 696 29.4 Concluding Remarks ............................ 708 References .................................................. 711 media boundaries, reflectance and transmittance, matrix methods and the application of these techniques to the design of antireflection coatings, mirrors and filters. The dependence of electrical conductivity (or resistivity) and the temperature coefficient of resistivity in metallic thin films is discussed, in particular the models of Thomson, Fuchs–Sondheimer and the grain-boundary model of Mayadas–Shatzkes. For insulating and semiconducting thin films the origin and effects of several high-field conduction processes are examined, including space-charge-limited conductivity, the Poole–Frenkel effect, hopping, tunnelling and the Schottky effect. Finally, some speculations regarding future developments are made.
Newton described observations of colours in thin films of transparent material and from geometrical considerations was able to calculate effective film thickness and correlate this with the periodicity of observed colours. The films in question were typically of air or water in the space between two glass surfaces having different radii of curvature. The phenomena described are seen most conveniently as Newton’s rings, where an optically flat glass surface is in contact with a convex glass surface having a large radius of curvature. Under monochromatic illumination in reflection, a series of concentric
Part C 29
This chapter provides an extended introduction to the basic principles of thin-film technology, including deposition processes, structure, and some optical and electrical properties relevant to this volume. The material is accessible to scientists and engineers with no previous experience in this field, and contains extensive references to both the primary literature and earlier review articles. Although it is impossible to
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