Conductors, thick-film microstructure

Pask J.A., Zhang X.W., Tomsia A.P., Yoldas B.E. Effect of sol-gel mixing on mullite microstructure and phase equilibria in the a-Al203-Si02 system. J. Am. Ceram. Soc. 1987 70 704-707 Perthuis H., Colomban Ph. Li eucryptite superionic conductors thick films. J. Mater. Sci. Lett. 1985 4 344-346... 

Figure 3-5 The differences in the microstructures of a thick film processing conductor formed on an alumina substrate and an LTCC conductor.

Microstructural features of dielectric materials include the chemical composition and structure of the various phases as well as porosity and its distribution. These microstructural features, coupled with macroscopic defects such as pinholes, mesh marks, foreign matter, and interaction with conductor materials, determine dielectric properties. Very little information is published about composition of thick-film dielectrics, which are complex materials systems. The following section is a general discussion of dielectric microstructure development. 

In this mode, a small SECM tip is used to penetrate a microstructure, for example, a submicrometer-thick polymer film containing fixed redox centers or loaded with a redox mediator, and extract spatially resolved information (i.e., a depth profile) about concentrations, kinetic- and mass-transport parameters [33, 34]. With a tip inside the film, relatively far from the underlying conductor or insulator, solid-state voltammetry, at the tip can be carried out similarly to conventional voltammetric experiments in solution. At smaller distances, the tip current either increases or decreases depending on the rate of the mediator regeneration at the substrate. If the film is homogeneous and not very resistive, the current-distance curves are similar to those obtained in solution. 

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