Film Microstructure

Chemical solution deposition (CSD) procedures have been widely used for the production of both amorphous and crystalline thin films for more than 20 years.1 Both colloidal (particulate) and polymeric-based processes have been developed. Numerous advances have been demonstrated in understanding solution chemistry, film formation behavior, and for crystalline films, phase transformation mechanisms during thermal processing. Several excellent review articles regarding CSD have been published, and the reader is referred to Refs. 5-12 for additional information on the topic. Recently, modeling of phase transformation behavior for control of thin-film microstructure has also been considered, as manipulation of film orientation and microstructure for various applications has grown in interest.13-15... 

Precursor Structure Effects. The precursor structure can impact a broad range of properties, including crystallization temperature, the formation of intermediate phases during thermal treatment and film density, among other properties. Table 2.4 reports some of the key precursor properties that may affect densification and crystallization behavior, as well as the final film microstructure. 

Because of the complexities involved in understanding cause-effect relationships, an alternative approach to control the thin film microstructure has been pursued by some investigators—the use of statistically designed experiments to identify key processing parameters.114115 In these approaches, as illustrated in Table 2.6 for a Plackett-Burman screening study,114 limiting values for various experimental parameters are chosen. Films are then prepared from solutions synthesized under these conditions, and resulting film... 

Crean, G. M., Somekh, M. G., Golanski, A., and Oberlin, J. C. (1987). The influence of thin film microstructure on surface acoustic wave velocity. IEEE 1987 Ultrasonics Symposium, pp. 843-7. IEEE, New York. [220]... 

The micromagnetic structure is directly related to the microstructure and chemical inhomogenities in the layer. The materials used and the deposition technology as well as the parameters play an important role. Thin-film growth, nudeation processes in relation to the deposition parameters, are very important for understanding the thin film microstructure. The relationships between sfd and recording properties are not necessarily valid for media with perpendicular anisotropy as the demagnetizing field can be more important than sfd. 

IR spectra measurements as well as variation of the film thickness, shrinkage, and refractive index demonstrated substantial differences in the mechanisms of thermal decomposition of films prepared from the exclusively metal alkoxide precursor and from the metal alkoxides modified by 2-ethylhexanoic acid. These differences affect the evolution of film microstructure and thus determine the different dielectric properties of the obtained films. The dielectric permittivity of the films prepared from metal alkoxide solutions was relatively low (about 100) and showed weak dependence ofthe bias field. This fact may be explained by the early formation of metal-oxide network (mostly in the... 

The reaction of toluene-2,4-diisocyanate with chlorine to l-chloromethyl-2,4-diisocyanatobenzene was carried out in a falling-film microstructured reactor with a transparent window for irradiation [264]. There are two modes of reaction. The desired radical process proceeds with the photoinduced homolytic cleavage of the chlorine molecules, and the chlorine radical reacts with the side chain of the aromatic compound. At very high chlorine concentrations radical recombination becomes dominant and consecutive processes such as dichlorination of the side chain may occur as well. Another undesired pathway is the electrophilic ring substitution to toluene-5-chloro-2,4-diisocyanate, promoted by Lewis acidic catalysts in polar solvents at low temperature. Even small metallic impurities probably from corrosion of the reactor material can enhance the formation of electrophilic by-products. 

Specimens that contain materials with very different ion-milling rates, such as metallic multilayers grown on silicon substrates, often tend to form bridges of material across the perforated area. Ion-milling at very low angles of incidence ( 1-2°) in a direction parallel to the interface can sometimes be used to overcome or at least alleviate these bridging problems. Finally, it should be noted that the use of a crystalline substrate such as silicon provides a convenient reference material for specimen orientation purposes in the TEM. Examination of the substrate EDP can be used to ensure that the substrate normal is aligned exactly perpendicular to the electron beam direction. The thin-film microstructure can then be easily determined. 

Refs. [i] BudevskiE, Staikov G, Lorenz WJ(1996) Electrochemical phase formation and growth. An introduction to initial stages of metal deposition. VCH, Weinheim, pp 4-6 [ii] Watanabe T (2004) Nano-plating. Microstructure control theory of plated film and data base of plated film microstructure. Elsevier, Amsterdam, pp 97-106... 

For both processes mentioned above, the bulk plasma characteristics (electron energy distribution function and plasma potential) are varied. It is thus difficult to distinguish whether the resulting film microstructure is controlled by processes in the plasma volume (for example different fragmentation of the monomer molecules) or by surface effects. 

The results described above demonstrate the utility of this AW technique [135] for characterizing thin film microstructure. This technique uses the well-established nitrogen adsorption isotherm technique commonly used to evaluate porous bulk samples. By increasing the sensitivity to the amount of adsorbed Na, this AW technique allows thin films to be characterized directly. 

Film Microstructure Microstructure provides a surface (to be polished) composed of differently oriented surfaces with different chemical and mechanical behaviors and grain boundaries that are prone to enhanced chemical activity. Thus a relationship between the film microstructure and planarization should be carefully monitored. 

Recent research on more coercive media with a low noise ratio involved addition of Zn to the Co alloy system [76-79]. Addition of Zn to the cobalt alloy very effectively produces a film with a fine particle structure, which results from codeposition of elements which are hardly soluble in the matrix. Such codeposition causes segregation and hence produces a film microstructure consisting of fine particles. The fine particulate structure lowers the noise ratio and increases the coercivity of the medium. 

Film hardness of electrodeposited Cu film was found to reduce over time at room temperature by 43%. The hardness reduction was caused by Cu film self anneal where Cu grains grow fi om the initial 0.1 pm at as-deposit to 1 pm at the final stage. The significant hardness reduction and changes in film microstructure resulted in a 35% CMP removal rate increase. This removal rate increase translates to variations in manufacturing environment and are therefore simply unacceptable. It was found that anneals at temperatures around 100°C for several minutes in inert gas will stabilize blanket Cu films and provide consistent CMP removal rate. 

Vlachos, D.G. (1999) Role of Macrotransport Phenomena in Film Microstructure during Epitaxial Growth. Appl. Phys. Lett., 74, 2797-2799. 

Mattoussi H., Radzilowski E. H., Dabbousi B. 0., Fogg D. E., Schrock R. R., Thomas E. E., Rubner M. F. and Bawendi M. G. (1999), Composite thin films of CdSe nanocrystals and a surface-passivating/electron-transporting block copolymer correlations between film microstructure by transmission electron microscopy and electroluminescence , J. Appl. Phys. 86, 4390-4399. 

Neu V, Shaheen SA (1999) Sputtered Sm-Co films microstructure and magnetic properties. J Appl Phys 86 7006-7009... 

A particularly illustrative example of the dependence of film microstructure on the size, structure, and condensation rate of the depositing silicate phase is that of a borosilicate sol deposited at pH 3 after various periods of aging at 50 °C (122). The borosilicate species are characterized by a mass fractal dimension D — 2.4. Aging at 50 °C causes them to grow in size as indicated by the plot of hydrodynamic radius versus aging time in Figure 18. Corresponding refractive indices of films deposited from the... 

Zanfir, M., Gavriilidis, A., Zapf, R., Hessel, V., Carbon dioxide absorption in a falling film microstructured reactor Experiments and modeling, Ind. Eng. Chem. Res. 44(6) (2005) 1742-1751. 

Protein Films Microstructural Aspects and Interaction with Water... 

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