Thin film fabrication

Fabrication techniques for producing thin films of nonlinear polymers must be capable of yielding controlled thickness with submicrometre accuracy over large substrate areas and with uniform refractive indices. Particulate contamination must be minimized, usually necessitating clean-room facilities, high-purity materials, submicrometre filtering and 

The most widely used technique for producing thin films of polymeric material is spin coating from solution. This technique is widely used in microelectronics fabrication to produce thin films of photoresist for photolithographic processes (Chapter 2). For this application, the thickness and uniformity of the photoresist must be accurately controlled, and to this end precision spin-coating machines have been developed offering accurate acceleration and spin speeds typically between 1000 and 10000revmin The requirement of polymeric thin films for optical purposes are very similar, and spin-coating techniques have been used to produce exceptionally low-loss structures [139]. 

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Alternative Thin-Film Fabrication Approaches. Thin films of electronic ceramic materials have also been prepared by sputtering, electron beam evaporation, laser ablation, chemical beam deposition, and chemical vapor deposition (CVD). In the sputtering process, targets may be metal... 

The third general classification of solution synthesis approaches used for inorganic electronic thin film fabrication is referred to as metallo-organic decomposition, or MOD for short.23-29,37,38,85 Historically long-chain carboxylate compounds, such as lead 2-ethylhexanoate, zirconium neodecanoate, and titanium di-methoxy di-neodecanoate have been used.23-29,85 Both commercially available precursors and in-house synthesized starting reagents have been used. 

Schwartz, R. W. Reichert, T. L. Clem, P. G. Dimos, D. Liu, D. 1997. A comparison of diol and methanol-based chemical solution deposition routes for PZT thin film fabrication. Int. Ferro. 18(l-4) 275-286. 

Temperature control is one of the longest established and most important functions in household appliances. One example of modern thin film fabrication technology of platinum temperature sensors with application examples in the kitchen in hot plates and ovens is given in Chapter 5.1. 

Dr. Hui has worked on various projects, including chemical sensors, solid oxide fuel cells, magnetic materials, gas separation membranes, nanostruc-tured materials, thin film fabrication, and protective coatings for metals. He has more than 80 research publications, one worldwide patent, and one U.S. patent (pending). He is currently leading and involved in several projects for the development of metal-supported solid oxide fuel cells (SOFCs), ceramic nanomaterials as catalyst supports for high-temperature PEM fuel cells, protective ceramic coatings on metallic substrates, ceramic electrode materials for batteries, and ceramic proton conductors. Dr. Hui is also an active member of the Electrochemical Society and the American Ceramic Society. 

Thin film technology is becoming one of the important technologies today. While there are infinite varieties of thin film fabrication methods, most amorphous thin films seem to exhibit fractal-like atomic structures. Depending on the fabrication conditions, a thin film grows on the substrate into columnar structures with many voids interdispersed in the thin film.80 These structures can be seen in the field ion microscope, and compositional variation can be analyzed with the atom-probe. In addition, formation of atomic clusters inside the thin film can be substantiated with the observation of a large fraction of cluster ions in field evaporation by the atom-probe. 

M. Sayer and K. Sreenivas, Ceramic thin films fabrication and applications. Science 247, 1056-1060 (1990). 

Sayer, M. and K. Sreenivas "Ceramic Thin Films Fabrication and Applications, ... 

Shieh K-J, Li M, Lee Y-H, Sheu S-D, Liu Y-T, Wang Y-C. Antibacterial performance of photocatalyst thin film fabricated by defection effect in visible light. Nanomed Nanote-chnol Biol Med 2006 2 121-6. 

Wong, E.M. and P.C. Searson (1999). ZnO quantum particle thin films fabricated by electrophoretic deposition. Applied Physics Letters, 74(20), 2939-2941. 

Rare earth silicates exhibit potential applications as stable luminescent materials for phosphors, scintillators, and detectors. Silica and silicon substrates are frequently used for thin films fabrication, and their nanostructures including monodisperse sphere, NWs are also reliable templates and substrates. However, the composition, structure, and phase of rare earth silicates are rather complex, for example, there are many phases like silicate R2SiOs, disilicate R2Si207 (A-type, tetragonal), hexagonal Rx(Si04)602 oxyapatite, etc. The controlled synthesis of single-phase rare earth silicate nanomateriais can only be reached with precisely controlled experimental conditions. A number of heat treatment based routes, such as solid state reaction of rare earth oxides with silica/silicon substrate, sol-gel methods, and combustion method, as well as physical routes like pulsed laser ablation, have been applied to prepare various rare earth silicate powders and films. The optical properties of rare earth silicate nanocrystalline films and powders have been studied. 

The modem silicon-based microelectronics led to the miniaturization of electronic devices. However, delays caused by metallic intercoimec-tions became a bottleneck for the improvement of their performances. One possible solution of this problem is to use optical intercoimections for the transfer of information, and, therefore, silicon compatible materials and devices that are able to generate, guide, amplify, switch, modulate, and detect light are needed. Rare earth silicates with luminescent rare earths and compatibility with silicon may be a good choice for these applications (Miritello et al., 2007). Miritello et al. presented the study on nanocrystalline erbium silicate thin films fabricated on silicon/silica substrates. The obtained films exhibit strong photoluminescence emission around 1540 nm with room temperature excitation by 488 ran Ar laser. 

FIGURE 6.8. Schematic diagram of conformations of polymer chains in thin films fabricated with different spin speeds and from solutions with different concentrations. 

Recently, n-channel transistors of poly(9,9-di-n-octylfluorene-alt-benzothiadia-zole) (51d) have been reported using thin films fabricated by spin-coating.[298] Electron mobilities ranging from 6 x lO. S x 10 cm V s were observed with the use of a 50 nm BCB polymer layer on top of the Si02 dielectric and Ca electrodes. Alternating copolymers containing 1,3,4-heterodiazoles and fluorenes have also been synthesized and show very low n-channel mobilities (2.2 x 10 cm V s for compound 51e).[299]... 

Ichihashi T, Tanigaki K, Ebbesen T W, Kuroshima S and lijima S 1992 Structures of Cgg thin films fabricated on alkali halide substrates by organic MBE Chem. Phys. Lett. 190 179-83... 

Recently, efforts have been devoted to the fabrication and characterization of PbZri- Ti c03 family thin films for their potential applications in nonvolatile memory devices (See Ref. 17, for example). Partly because of the convenient stoichiometry control during processing, it was found that chemical methods, such as sol-gel and metal organic decomposition (MOD), are superior to physical means in many aspects. To appreciate better the science and technology of ferroelectric thin-film fabrication, it is important to give a brief account of the past efforts and the present status and, it is hoped, shed some light on the future. 

Sakai G., BaikN. S., MiuraN., and YamazoeN., Gas sensing properties of tin oxide thin films fabricated from hydrothermally treated nanoparticles Dependence of CO and H2 response on film thickness. Sens. Actuators B, 77, 116-121, 2001. 

Thin films fabricated include two types of particles with mean diameters of 1.4 nm (o=0.11) and 6.3 nm (o=0.18). The TEM image of nanoparticles in PEPC film was the same for those obtained for colloidal dispersions containing PEPC. 

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