Insulating dielectrics

Dielectric films Dielectric fluids Dielectric insulators Dielectric masking Dielectric materials Dielectric permittivity Dielectrics... 

For low frequency electrical insulation appHcations, the dielectric constant of the insulation is ideaUy as low as possible (see Insulation, electrical). The lower the density of the ceUular polymer, the lower the dielectric constant and the better the electrical insulation. Dielectric strength is also reduced at... 

This force equation can now be used to find the force in model systems such as that of an ideal dielectric sphere (relative dielectric constant Ko) in an ideal perfectly insulating dielectric fluid (relative dielectric constant K ). The force can now be written as... 

The principle of these anodes is similar to that of platinised titanium since they are all valve metals that form an insulating dielectric film under anodic polarisation. 

Moisture and vapor penetration Condensation Electrical insulation Dielectric properties... 

Insulator (dielectrics) Alumina Silicon oxide Silicon nitride Glass Bound to nucleus 1012 to 1022... 

By the nature of conduction and values of conductivity, materials can be classified as conductors, semiconductors, or insulators (dielectrics). It is a special attribute of conductors that free electric charges are present in them. The migration of these free charges in an applied electric field manifests itself as electric current. 

Synthetic polymers are best known for their insulating dielectric properties which have been exploited for numerous applications in both the electrical and electronic industries. It was found recently that some polymers can also be rendered conductive by an appropriate treatment, thus opening the way to a new field of applications of these materials (2, 3). Usually, electrical conductivity is obtained by doping a neutral polymer, rich in unsaturation, with donor or acceptor molecules. These polymers are rather difficult to synthesize, which makes them very expensive besides they are often sensitive to environmental agents, like oxygen or humidity, thus restricting their practical use to oxygen-free systems. 

Figure 9. Propagating brush discharges, (a) Insulating dielectric layer of dielectric permittivity e thickness dlayer, and surface charge ey with conductive backing, (b) Example of improper use of plastic (PVC) pipe where surface charge builds up leading to risk of propagating brush discharge.

These postulated mechanisms3 are consistent with the observed temperature dependence of the insulator dielectric properties. Arrhenius relations characterizing activated processes often govern the temperature dependence of resistivity. This behavior is clearly distinct from that of conductors, whose resistivity increases with temperature. In short, polymer response to an external field comprises both dipolar and ionic contributions. Table 18.2 gives values of dielectric strength for selected materials. Polymers are considered to possess... 

Donor-doped BaTi03 is the basis of positive temperature coefficient (PTC) resistors (see Section 4.4.2). The insulating dielectrics formed with high donor concentrations have a low oxygen vacancy content and are therefore less prone to ageing and degradation. 

Annu. Rep.—Conf. Electr. Insul. Dielectr. Phenom. 

Wagner (1914) gave an approximate treatment of the important practical case where a very highly insulating dielectric suffers from inclusions of conductive impurities. Taking the model where the impurity (relative permittivity e2, conductivity a2) exists as a sparse distribution of small spheres (volume fraction f) in the dielectric matrix (relative permittivity e, negligible conductivity), he derived equations for the components of the complex relative permittivity of the composite ... 

PlO-14 Titanium dioxide is a wide-bandgap semiconductor that is showing promise as an insulating dielectric in VLSI capacitors and for use in solar cells. Thin films of T102 are to be prepared by chemical vapor deposition from gaseous titanium tetraisopropoxide (TTIP). The overall reaction is... 

Among important previous applications of PCB mixtures are hydraulic fluids, insulation dielectrics in transformers and condensers, plasticizers in plastics, outdoor paints and printer s ink and different sealing and construction products for building and mounting purposes. 

Copper is going to replace aluminum as the material of choice for semiconductor interconnects due to its low electrical resistance and high electromigration resistance (1-4). An inlaid interconnect is used for copper metallization in which the insulating dielectric material is deposited first, trenches and vias are formed by patterning and selective dielectric etching, and then diffusion barrier and copper seed layer are deposited into the trenches and vias (5). 

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