Thin film thickness

K. C. Mittal, ed., Mdhesion Measurements of Thin Films, Thick Films and Bulk Coatings, ASTM STP, Philadelphia, Pa., 1978, p. 640. 

Thickness gaging, of steel strip, 69-71 use of cobalt-60 for, 291 Thick-target x-ray spectra, 6, 7, 99-101 Thin films, thickness determined by characteristic line intensity, 153 Thin samples, analysis by x-ray emission spectrography, 167... 

Flow of trains of surfactant-laden gas bubbles through capillaries is an important ingredient of foam transport in porous media. To understand the role of surfactants in bubble flow, we present a regular perturbation expansion in large adsorption rates within the low capillary-number, singular perturbation hydrodynamic theory of Bretherton. Upon addition of soluble surfactant to the continuous liquid phase, the pressure drop across the bubble increases with the elasticity number while the deposited thin film thickness decreases slightly with the elasticity number. Both pressure drop and thin film thickness retain their 2/3 power dependence on the capillary number found by Bretherton for surfactant-free bubbles. Comparison of the proposed theory to available and new experimental... 

Here, h is the constant thin film thickness obtained by o J... 

The main results of our first-order regular perturbation analysis are the expressions for the constant thin film thickness, hQ, and for the total hydrodynamic pressure drop across the entire... 

The first term in both Equations 17 and 18 is the constant surface-tension contribution and the second term gives the first-order contribution resulting from the presence of a soluble surfactant with finite sorption kinetics. A linear dependence on the surfactant elasticity number arises because only the first-order term in the regular perturbation expansion has been evaluated. The thin film thickness deviates negatively by only one percent from the constant-tension solution when E = 1, whereas the pressure drop across the bubble is significantly greater than the constant-tension value when E - 1. 

The quality of the thin film depends on preferential interactions between precursor and coating substrate. However, the initial layer is clearly the most important and, in the case of nanocarbons, the surface chemistry must be tailored. For most ALD precursors, hydrophilic surface groups enhance deposition, which can be achieved by functionalizing the nanocarbon prior to placement in the ALD reaction chamber or by treating the sample within the chamber with reactive plasma. Among the many in situ hybridization techniques, ALD provides best control of thin film thickness. 

The in situ wet chemical approach requires less nanocarbon modification, especially for electrodeposition, and can produce thin, uniform, multilayer films. This is the method of choice for nanocarbon-polymer hybrids as the increased interfacial area reduces problems of nanocarbon insolubility and subsequent aggregation. Gas phase deposition offers the greatest control of thin film thickness but is suitable almost exclusively to the deposition of metals and metal oxides. 

The effect of wind velocity on (a) thin-film thickness and (b) piston velocity. The solid line represents results obtained from measurements made in wind tunnels. In situ measurements were made from distributions of the naturally occurring radioisotopes of carbon and radon. Source From (a) Broecker, W. S., and T.-H. Peng (1982). Tracers in the Sea. Lamont-Doherty Geological Observatory, p. 128, and (b) Bigg, G. R. (1996). The Oceans and Climate. Cambridge University Press, p. 85. 

Moreover, it is remarkable that a simple change of the substituents in the ligands (tert-hutyl rather than hydrogen) leads to a significant difference in the solubility of the polymers. Whereas polymer 14 (Rj at the ligands is H), for example, is absolutely insoluble in all common organic solvents, polymer 11 (Ri=H, R2=C(CH3)3) is completely soluble in acetone, acetonitrile, and DMSO. The polymers substituted with tert-butyl groups are also soluble in cyclohexanone. All the soluble polymers can be converted into transparent thin films (thickness between 150 nm and 3 pm). This is important for application in optical devices. 

Figure 3.18. Thin TTF-TCNQ film (thickness 1 um) HV-grown on a KCl(lOO) substrate, (a) Topography and (b) amplitude TMAFM images. The scale is 5 p.m x 5 ]xm. (c) FTIR spectra of the CN stretching mode in neutral TCNQ (powder) and in a TTF-TCNQ thin film (thickness 1 um) HV-grown on KBr(lOO). Reprinted from Surface Science, Vol. 482 85, C. Rojas, J. Caro, M. Grioni and J. Fraxedas, Surface characterization of metallic molecular organic thin films tetrathiaful-valene tetracyanoquinodimethane, 546-551, Copyright (2001), with permission from Elsevier.

Figure 3.19. XRD pattern of a thin film (thickness 1 pm) of the a-phase of p-NPNN HV-grown on a glass substrate. The inset shows the rocking curve of the (004) reflection. Reprinted with permission from J. Fraxedas, J. Caro, J. Santiso,...

Figure 5.7. Optical microscope image of a thin film (thickness 2 p.m) of a-p-NPNN grown on a glass substrate (1.6 x 1.0 mm, crossed polarizers). Reprinted from Journal of Crystal Growth, Vol. 209, J. Caro, J. Fraxedas and A. Figueras, Thickness-dependent spherulitic growth observed in thin films of the molecular organic radical p-nitrophenyl nitronyl nitroxide, 146-158, Copyright (2000), with permission from Elsevier.

Figure 5.11. TMAFM image of a thin film (thickness 1 am) of a -/7-NPNN on NaCl(lOO) 1 am x 1 am. Reprinted from Surface Science, Vol. 415, J. Fraxedas, J. Caro, A. Figueras, R Gorostiza andF. SsLnz,Dislocationhollow cores observedon surfaces of molecular organic thin films p-nitrophenyl nitronyl nitroxide radical, 241-250, Copyright (1998), with permission from Elsevier.

Although the detailed information on the polymorphic phases has to be obtained with e.g., diffraction and scanning probe methods, our eyes are attracted by the beauty of optical microscope images often encountered with polymorphs under transformation. Figure 5.17 shows an optical microscopy image of a / -NPNN thin film (thickness 2 pm) on a glass substrate, exhibiting a transformation at... 

Good, R. J. In Adhesion measurement of thin films, thick films and bulk coatings. K. L. Mittal, (ed.) ASTMSTP 640, ASTM, Philadelphia, PA., 1978, p. 41... 

This situation may represent the diffusion of a high-vapor-pressure dopant out of a thin film (thickness L, initial dopant concentration c0) of silicon when placed in a vacuum. Assume that the variables are separable.7 Letting c(x,t) = X(x)T(t) and substituting into the diffusion equation gives... 

Figure 9. A schematic diagram of the interferometer used to measure thin film thickness. The inset shows that light is both transmitted and reflected by the thin film. Reproduced from reference [7] with the permission of the Royal Society of Chemistry.

Figure 17. A summary of the bulk foam stability ( ), equilibrium thin film thickness (o), and FITC-a-la surface diffusion (A) as a function of molar ratio of Tween 20 to protein (R). The concentration of a-la was 0.5 mg/ml (35.4 piM). Reproduced from reference [41] with the permission of VCH Verlagsgesellschaft.

Because, as stated above, alpha particles are so easily absorbed by matter, their main uses in radiogauging have been to measure very thin film thickness and gas density, temp and pressure. Alpha particles lose their energy in matter primarily by ionization. The range of alpha particles in air, as a function of energy, can be estimated from the empirical expression (Ref 8) ... 

Hi) 2D must be capable of giving fast GC results, achieved by a combination or all of the following, i.e. a short column, thin film thickness, narrow id column (giving high carrier linear velocity) and higher temperature (if a two-oven system is used) ... 

Fig. 10 Simulation results for a cylinder-forming A3B12A3 (6ab = 6.5) in thin films (thickness = 6 nm = ao) with varied strength of the symmetric surface field The isodensity profiles (Pa = 0.45) are shown for indicated simulation parameters. Reprinted from [58], with permission. Copyright 2004 American Institute of Physics...

Figure 7. Clamping setup for controlling the thin-film thickness of the sample...

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