Thin-Film Properties and Applications

Both 6FDA-PFMB and BPDA-PFMB could be solution-cast into 1-100-pm-thick tough films. 6FDA-PFMB was cast from ketone or ether solutions, and the less-soluble BPDA-PFMB was cast from phenolic solutions. The films were 

Above the critical intrinsic viscosity of 1.1 dPg, both refractive index values remained relatively constant. Thus, the UNB initially increased with increasing intrinsic viscosity and then reached a maximum above the critical intrinsic viscosity. Lowering the molecular weight may disrupt the packing owing to 

Relative to microelectronic applications, the out-of-plane dielectric constant for BPDA-PFMB films measmed after aging at 50% relative humidity for 48 h at 23°C was between 2.8 and 2.9 (0.1 kHz to 1 MHz) (ASTM D-150-81These values are considerably lower than that of commercial polyimides such as PMDA-ODA (pyromellitic dianhydride, PMDA) (s = 3.5 at 1 kHz and 3.3 at 10 MHz). The dielectric constant and tan 8 (dissipation factor) were temperature- and frequency-dependent. The dielectric constant, which was independent of temperature until near 210°C increased above this point until a frequency-dependent maximum was reached at about 290°C. The dissipation factor, which was also independent of temperatme below 200°C, underwent a rapid increase with no maximum between 200 and 400°C owing to ion conductivity. The temperatme at which this increase occurred increased as the frequency increased. The films also 

---

Karapatnitski, LA., Mit, K.A., Mukhamedshina, D.M., Baikov, G.G. (2000). Effect of hydrogen plasma processing on the structure and properties of tin oxide thin film produced by magnetron sputtering. Proc. of the 4th Int. Conf. on Thin Film Physics and Applications, 8-11 May, 2000. Shanghai, China. Vol. 4086, p. 323. 

He, J.A., Samuelson, L., Li, L., Kumar, J. and Tripathy, S.K. (1999) Bacteriorhodopsin thin film assemblies-immobilization, properties and applications. Advanced Materials, 11, 435-446. 

Mechanical Properties. The mechanical properties of thin films is affected by the film density and composition. In many applications, the properties of the substrate material is important to the functionality of the thin film in mechanical applications. 

In the following, each step will be described, both for the AP-CVD and for the LP-CVD cases. The results presented are focused on those properties of ZnO films that are useful for thin film solar cell applications, i.e., transparency, conductivity, and light scattering capability. The last part of paragraph 6.2 comments briefly on alternative methods of CVD processes that have been investigated for ZnO deposition (PE-CVD, photo-CVD,. ..). 

This book is devoted to the properties, preparation and applications of zinc oxide (ZnO) as an transparent electrode material. It focuses on ZnO for thin film solar cell applications and hopefully inspires also readers from related fields. The book is structured into three parts to serve both as an overview as well as a data collection for students, engineers and scientists. The first part, Chaps. 1-4, provide an overview of the application and fundamental material properties of ZnO films and their surface and interfaces properties. Chaps. 5-7 review thin film deposition techniques applied for ZnO preparation on lab scale but also for large area production. Finally, Chaps. 8 and 9 are devoted to applications of ZnO in silicon- and chalcopyrite-based thin film solar cells, respectively. One should note that the application of CVD grown ZnO in silicon thin film cells is discussed earlier in Chap. 6. 

Tomonari, M., Ookubo, N. and Takada, T. (1997). Chem. Phys. Lett. 266, 488 IWieg, R. J. and Dirk, C. W. (1996). Design, properties and applications of nonlinear optical chromophores. In Science and Technology of Organic Thin Films for Waveguiding Nonlinear Optics (eds F. Kajzar and J. Swalen), Gordon and Breach, Amsterdam, p. 45... 

In this chapter, we explore the current and potential future applications of AW devices for materials characterization and process monitoring. Because of the limited mass of material that can be applied to the AW device surface, the majority of these applications deal with the chemical and physical characterization of thin-film properties. This thin film focus should not be thought of as a limitation of AW devices, but rather as a useful capability — the direct measurement of properties of materials in thin-film form. Since material properties can depend on the physical form (e.g., film, bulk) of the material (see Section 4.3.1.3), AW devices are uniquely suited to directly characterize thin-film materials. These considerations also indicate that even though it is possible to use AW thin-film data to predict bulk material properties, such extrapolations should be performed with care. 

In conclusion, the results presented in this chapter demonstrate the extreme versatility of AW devices for the characterization of materials. The inherent sensitivity of AW properties to the mechanical and electrical properties of thin films can be used to advantage to directly monitor a wide variety of film properties. Since the properties and behavior of thin-film materials can be very different from those of similar bulk materials, this ability to directly measure thin film properties can be a significant advantage in materials research and development. The ability to use thin films instead of bulk samples has the added advantage that the time required to perform an evaluation of dynamic processes such as diffusion and corrosion can be greatly decreased. The number of applications of AW devices to thin-film characterization continues to increase, and is limited only by the ingenuity of AW device researchers and developers. 

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 dry nature of CVD process enables copolymerization more easily than solution based techniques. This approach has been utilized to tailor the thermal and electrical properties of parylene thin films for ULSI applications. One of the first reports of vacuum copolymerization of xylylene was done with maleic anhydride as the comonomer. Subsequently, 9-vinylanthracene, 4-vinylbiphenyl and perfluoro-octyl methacrylate were successfully copolymerized with parylenes, and reported in... 

---