Thin-film process definition

The line definition available by the thin-film process is considerably better than that of the thick-film process. Consequently, the thin-film process operates much better at high frequencies. 

The ideal route would be one in which the pyroelectric detector material is laid down in thin film form by a route compatible with the production of the silicon ROIC. There are obvious parallels with the development of FeRAMS (see Section 5.7.5) and the substantial effort now devoted to their development will have a positive impact on the manufacture of pyroelectric arrays. Challenges he in the requirement to process the deposited films at temperatures not too high for the underlying integrated circuit, and the need to engineer the temperature diffusion characteristics within the element and its surroundings so as to optimise image definition. 

Early work in this field was conducted prior to the availability of powerful radiation sources. In 1929, E. B. Newton "vulcanized" rubber sheets with cathode-rays (16). Several studies were carried out during and immediately after world war II in order to determine the damage caused by radiation to insulators and other plastic materials intended for use in radiation fields (17, 18, 19). M. Dole reported research carried out by Rose on the effect of reactor radiation on thin films of polyethylene irradiated either in air or under vacuum (20). However, worldwide interest in the radiation chemistry of polymers arose after Arthur Charlesby showed in 1952 that polyethylene was converted by irradiation into a non-soluble and non-melting cross-linked material (21). It should be emphasized, that in 1952, the only cross-linking process practiced in industry was the "vulcanization" of rubber. The fact that polyethylene, a paraffinic (and therefore by definition a chemically "inert") polymer could react under simple irradiation and become converted into a new material with improved properties looked like a "miracle" to many outsiders and even to experts in the art. More miracles were therefore expected from radiation sources which were hastily acquired by industry in the 1950 s. 

In order to find the domain of LCVD, it is necessary to compare various vacuum deposition processes chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma chemical vapor deposition (PCVD), plasma-assisted CVD (PACVD), plasma-enhanced CVD (PECVD), and plasma polymerization (PP). All of these terms refer to methods or processes that yield the deposition of materials in a thin-film form in vacuum. There is no clear definition for these terms that can be used to separate processes that are represented by these terminologies. All involve the starting material in vapor phase and the product in the solid state. 

Polyester is mainly melt-spun into fibers. A smaller quantity is used for very thin films for the electrical industry. Higher molecular weight poly(ethylene terephthalate) with added nucleating agents (salts of carboxylic acids) can also be used as thermoplastic synthetics. A definite disadvantage of polyester fiber is that it yellows in light. The mechanism for this process... 

Surface analysis is a complex matter. The complexity starts by the definition of the term surface itself. Not everyone understands the same by surface. We often hear and speak about the surface of Earth or Mars, about the inner surfaces of a zeolite, about the existence of surface processes such as corrosion or adhesion, and so on. Depending on the field or the particular application, we talk about different things that have, however, a common characteristic. In all the cases, the surface is a border region that separates the solid (the bulk) from the environment (liquid or gaseous). It is the thickness of this border region, and what happens within this thickness, that determines the characteristics of many processes that are relevant in both basic science and technology. This thickness may extend from a few atomic layers (and thus be the subject of surface science ) to a few nanometers (surface analysis) or afraction of a micrometer (thin film analysis). Thus, in this chapter the term surface represents the external part of a solid having a thickness from a fraction of a monolayer to a few nanometers. 

The analysis of the statistical or preferred orientation of the crystallites in solid polycrystaUine materials is commonly referred to as texture analysis. Again, the diffraction technique allows the definition of the relationship between a microscopic property, i.e. the orientation of the crystallites defined as coherent diffraction domains, and the macroscopic physical properties of the crystal aggregate. Texture studies are of course crucial in the characterization of oriented synthetic materials such as cold-rolled metals or oxide thin films, but they are also of great relevance in the study of the formation processes of mineral assemblages. As an example, the texture features of olivine or pyroxene minerals in meteoritic chondrules yield information on the early condensation sequence... 

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