Organic film volatile

Unlike silicon-based materials where selective reactants are of ultimate importance, and III-V and metallic materials where product volatility dominates etching considerations, selective etching of organic films is driven by incorporating the desired reactivity (or lack of it) into the film itself. In device fabrication all types of materials are present simultaneously and the process engineer must be aware of the important aspects of the chemistry of each material in addition to the gas phase reactions that produce chemically active species. It is hoped that the discussions presented here provide a basis for approaching such a complex chemical system and for critically evaluating studies which appear in the literature. 

As an example for depth profiling of interfaces, we present an XPS investigation of the ferroelectric copolymer P(VDF-TrFE). This material opens an opportunity for organic non-volatile memories. A prerequisite for low operation voltages is a downscaling of the film thickness, where interface phenomena between the electrode and the copolymer become important. We eompare the two interfaces P(VDF-TrFE)/Al and P(VDF-TrFE)/PEDOT PSS. 

Several studies indicate that the inhibitor blends are effective in solutions whereas pure solvents as dimethylethanolamine are not [1]. A commercial migrating inhibitor blend could be fractionated into a volatile (dimethylethanolamine) and a non-volatile (benzoate) component (9). For complete prevention of corrosion initiation in saturated Ca(OH)2 solution with 1 M NaCl added, the presence of both components at the steel surface in a concentration ratio of inhibitor/chloride of about one was necessary (Figure 13.3). Modern surface analytical techniques such as XPS have confirmed that for the formation of a significantly thicker and protective organic film on iron in aUcahne solutions, both components of the commercial inhibitor blend have to be present (10). Experiments with inhibitor added to mortar showed similar results the inhibitor blend admixed in the recommended dosage could delay the average time to corrosion initiation of passive steel in mor-... 

Current mathematical descriptions of the volatilization process date from the pioneering work of Whitman (39), who in the 1920s demonstrated that a two-film or two-resistance model gave an adequate description of interphase transfer processes of this type. Liss (16) and Liss and Slater (20) applied this concept to environmental transfer processes in the 1970s, and the concept was also used by Mackay and Leinonen (24) and Mackay (2/) in describing volatilization of organic compounds. Volatilization is placed in context with other environmental transport processes in the text by Thibodeaux (36). 

Poly(pPIN) was used as a spray adjuvant in pesticide applications to crops to increase their deposition and to decrease their rate of decay, which resulted in increased efficiency [98]. This effect is achieved through the formation of an organic film covering the crop foliage, which protects the active component from rain and wind erosion as well as volatilization. 

As their name implies, plasticizers are additives that soften a material, enhancing its flexibility. The worldwide market for plasticizers is currently over five million metric tons, with over 90% used to soften PVC. The most common plasticizers are phthalates however, due to the relatively high vapor pressure of these compounds, plasticizers will evaporate from the polymer structure as evidenced by the new car smell of new cars, as well as the organic film that becomes deposited on the interior windshield surface. For these applications, it is best to use a plasticizer with a lower volatility such as trimellitates. 

Dimethylcadmium has found use as a volatile source of Cd for metal organic chemical vapor deposition (MOCVD) production of cadmium-containing semiconductor thin films (qv) such as CdS, Cdi 2 Hg -Te, or Cdi 2 Mn -Te, as multiple quantum weU species (32). Semiconductor-grade material seUs for... 

Solution Deposition of Thin Films. Chemical methods of preparation may also be used for the fabrication of ceramic thin films (qv). MetaHo-organic precursors, notably metal alkoxides (see Alkoxides, metal) and metal carboxylates, are most frequently used for film preparation by sol-gel or metallo-organic decomposition (MOD) solution deposition processes (see Sol-GEL technology). These methods involve dissolution of the precursors in a mutual solvent control of solution characteristics such as viscosity and concentration, film deposition by spin-casting or dip-coating, and heat treatment to remove volatile organic species and induce crystaHhation of the as-deposited amorphous film into the desired stmcture. 

Organosols (Mix B, Table 12.5) are characterised by the presence of a volatile organic diluent whose function is solely to reduce the paste viscosity. After application it is necessary to remove the diluent before gelling the paste. Organosols are therefore restricted in use to processes in which the paste is spread into a thin film, such as in the production of leathercloth. Because of the extra processes involved, organosols have not been widely used, in Europe at least. 

Sample preparation for the common desorption/ionisation (DI) methods varies greatly. Films of solid inorganic or organic samples may be analysed with DI mass spectrometry, but sample preparation as a solution for LSIMS and FAB is far more common. The sample molecules are dissolved in a low-vapour-pressure liquid solvent - usually glycerol or nitrobenzyl alcohol. Other solvents have also been used for more specialised applications. Key requirements for the solvent matrix are sample solubility, low solvent volatility and muted acid - base or redox reactivity. In FAB and LSIMS, the special art of sample preparation in the selection of a solvent matrix, and then manipulation of the mass spectral data afterwards to minimise its contribution, still predominates. Incident particles in FAB and LSIMS are generated in filament ionisation sources or plasma discharge sources. 

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