Substrate crystalline

Thin-film dielectrics (Ba0 92Ca108)(Ti0 92Zr0 08)O3 for the thin-film capacitors were prepared using Ba, Ca, and Zr ethoxides and Ti isopropoxide in refluxed methoxyethanol solutions as precursors. Films were deposited on a usual platinized Si substrate. Crystalline thin films after heat treatment at 800°C demonstrated dielectric permittivity of 1200, dielectric loss of0.5%, nonlinear coefficient a = 0.92, and break-down voltage of980 V [1595],... 

Among simple, non-O-containing anions, fluoride is one of the most active and important, and the adsorption of F" has been investigated due to its environmental importance (Fan, Paiker, and Smith 2003 Mohapatra et al. 2009 and references therein). Fluoride has been found to enter the substrate crystalline lattice by solid diffusion and/or ion exchange mechanism (Fan, Paiker, and Smith 2003). 

The substrates were tested at 0.05 M in the presence of 0.005 M cysteine and 0.001 M Versene at 39° at enzyme concentrations from 0.006 to 0. mg. of protein N per milliliter, the larger amounts bring required for the least sensitive substrates. Crystalline mocuripiqiain was used for these studies. 

Controlled preparation of thin films of P(DiAc)s can be obtained by topochemical (solid state) polymerization of thin films of monomer previously deposited by evaporation under high vacuum, followed by UV or gamma irradiation [569] such thin films possess high order and alignment. Variation of the substrate crystallinity yields thin films or crystals of varying crystallinity [569]. Innovative methods, such as application of pressure on a mobile monomer phase between two optical plates... 

The oriented overgrowth of a crystalline phase on the surface of a substrate that is also crystalline is called epitaxial growth [104]. Usually it is required that the lattices of the two crystalline phases match, and it can be a rather complicated process [105]. Some new applications enlist amorphous substrates or grow new phases on a surface with a rather poor lattice match. 

There is a fair amount of work reported with films at the mercury-air interface. Rice and co-workers [107] used grazing incidence x-ray diffraction to determine that a crystalline stearic acid monolayer induces order in the Hg substrate. Quinone derivatives spread at the mercury-n-hexane interface form crystalline structures governed primarily by hydrogen bonding interactions [108]. 

In corrosion, adsorbates react directly with the substrate atoms to fomi new chemical species. The products may desorb from the surface (volatilization reaction) or may remain adsorbed in fonning a corrosion layer. Corrosion reactions have many industrial applications, such as dry etching of semiconductor surfaces. An example of a volatilization reaction is the etching of Si by fluorine [43]. In this case, fluorine reacts with the Si surface to fonn SiF gas. Note that the crystallinity of the remaining surface is also severely disrupted by this reaction. An example of corrosion layer fonnation is the oxidation of Fe metal to fonn mst. In this case, none of the products are volatile, but the crystallinity of the surface is dismpted as the bulk oxide fonns. Corrosion and etching reactions are discussed in more detail in section A3.10 and section C2.9. 

Figure C2.3.17. Model of half-cylindrical aggregates (hemimicelles) on a crystalline hydrophobic substrate, such as for tetradecyltrimethylammonium bromide on M0S2 [91], Adapted from figure 2 of [89],...

Silicon Epitaxy. A critical step ia IC fabricatioa is the epitaxial depositioa of sdicoa oa an iategrated circuit. Epitaxy is defined as a process whereby a thin crystalline film is grown on a crystalline substrate. Silicon epitaxy is used ia bipolar ICs to create a high resistivity layer oa a low resistivity substrate. Most epitaxial depositioas are doae either by chemical vapor depositioa (CVD) or by molecular beam epitaxy (MBE) (see Thin films). CVD is the mainstream process. 

Transmission electron microscopy (tern) is used to analyze the stmcture of crystals, such as distinguishing between amorphous siUcon dioxide and crystalline quartz. The technique is based on the phenomenon that crystalline materials are ordered arrays that scatter waves coherently. A crystalline material diffracts a beam in such a way that discrete spots can be detected on a photographic plate, whereas an amorphous substrate produces diffuse rings. Tern is also used in an imaging mode to produce images of substrate grain stmctures. Tern requires samples that are very thin (10—50 nm) sections, and is a destmctive as well as time-consuming method of analysis. 

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