Modeling of deposition

Plasma analysis is essential in order to compare plasma parameters with simulated or calculated parameters. From the optical emission of the plasma one may infer pathways of chemical reactions in the plasma. Electrical measurements with electrostatic probes are able to verify the electrical properties of the plasma. Further, mass spectrometry on neutrals, radicals, and ions, either present in or coming out of the plasma, will elucidate even more of the chemistry involved, and will shed at least some light on the relation between plasma and material properties. Together with ellipsometry experiments, all these plasma analysis techniques provide a basis for the model of deposition. 

Leggett (1992) Model of Deposition and Retention of Americium in the Human Respiratory... 

Kliment, V., J. Libich, and V. Kaudersova. Geometry of guinea pig respiratory tract and application of Landahl s model of deposition of aerosol particles. J. Hyg. Epidemiol. Microbiol. Immunol. 16 107-114, 1972. 

G. Federici et al., Modelling of deposition of hydrocarbon films underneath the divertor and in the pumping ducts of ITER, J. Nucl. Mater., in press... 

Analysis of these new data have led to intensive development of a version of the hypothesis of formation of the BIF which can be called the biogeo-chemical accumulation version. In the U.S.S.R., besides in the works by Khodyush (1969) and Kaukin (1969), this hypothesis has been developed in recent years by Mel nik (1973, 1975) and Belevtsev and Mel nik (1976) on the basis of geologic, geochemical, and physicochemical investigations, including thermodynamic calculations and experimental modeling. The factual data, their interpretation, and possible models of deposition of the BIF will be examined in more detail in this book. 

Models of deposition-rate distribution and shape change are likely to evolve in new directions as progress continues in the areas of alloy plating [76], electrodeposition of resists [77, 78], electrodeposition of composite materials [79], electrodeposited eompositionally modulated alloys [80], pulsed electrodeposition, and patterned electroless plating [81]. The success of electrodeposition in high-technology device fabrication will continue to depend on the degree to which rate-distribution effects can be understood, predicted, and controlled. 

The uniform layer model of deposition has been implicit since Sato [3] and Newson [11]. This model leads to difficulties for a support surface of about 200 square meters per gram. A 20 weight % coke would occupy about 400 square meters, and 20 weight % vanadium pentasulfide would occupy 200 square meters. After a few months of operations, there would be 5 to 6 monolayer equivalent of deposits on the surface, so that the original cobalt-molybdenum surface would be completely covered. The remaining catalyst activity must be attributed to the activities of nickel and vanadium, which is perhaps ten times lower for the HDS reaction. 

Merchant, T.P., Gobbert, M.K., Cale, T.S. and Borucki, L.J. (2000) Multiple Scale Integrated Modeling of Deposition Processes. Thin Solid Films, 365, 368-375. 

Physical vapor deposition (PVD) is a direct line of sight impingement deposition technique. At the low pressures employed in a PVD reactor, the vaporized material encounters few intermolecular collisions while traveling to the substrate, and modeling of deposition rates is a relatively straightforward exercise in geometry. 

Modeling of depositional environments is gradually becoming more accepted as a better means of predicting what happens to the coal seam and adjacent rocks beyond the outcrops and drill holes. Not only does it allow the geologist to extrapolate the presence and thickness of seams, but also to predict the rock type that overlies and underlies the coal. All of this information is important for mine planning. 

Hodes, M.S., Smith, K.A., Hurst, W.S., Bowers, Jr., W.J. and Griffith, P. (1997) Measurements and modeling of deposition rates from a near supercritical aqueous sodium sulfate solution to a heated cylinder, Proc. 32nd Nati Heat Transfer Confl2, HTO-350, ASME, New York. 

Figure 2.4 Models of deposition showing layer-by-layer deposition (Frank—van der Merwe), island growth (Volmer—Weber) and mixed (Stranski-Krastanov).

Fig. 1.4 EDP Venda Nova II power plant. Modelling of deposit materials...

Brook, J.R., L. Zhang, R Di-Giovanni, and J. Padro. 1999. Description and evaluation of a model of deposition velocities for routine estimates of air pollutant dry deposition over North America. Part I model development. Atmospheric Environment, 33 5037-5051. 

---