Dielectric electrode patterns

Fig. 10.23. The frame on the left shows current-voltage characteristics of an n-channel transistor formed with electrodes patterned by nanotransfer printing. Laminating these electrodes against a substrate (PET) that supports an organic semiconductor (FCuPc), a gate dielectric (GR) and a gate (ITO)...

I he ER efTecl depends on the applied electric field slrenglli, the frequency of the electric field, the particle conductivity, the particle dielectric properties, the particle volume fraction, temperature, water content, the liquid medium, even the electrode pattern, etc. Those parameters are reviewed in this chapter. 

Dielectric Constant and Dielectric Loss. Impedance measurement bridges are the most commonly used instruments for dielectric constant and dielectric loss measnrements for lie-quencies up to 10 MHz. A capacitor structure is built as a bottom electrode, top electrode, and two or more separation layers of dielectric material. Figure 8.44 shows a typical electrode pattern. The outside guard ring on the top electrode pattern prevents measurement errors due to fringe effects. Dielectric constant and dielectric loss measurements at frequencies... 

A positive mode dichroic LCD [16, 127] can be demonstrated by using special electrode patterns even in the case of pleochro-ic dyes embedded in a liquid crystal of positive dielectric anisotropy. In this case the voltage is applied to the whole visible area and is removed only from the desired segmented areas. 

Figure 12.5. Photograph of microdispensing system depositing an inorganic dielectric dispersion onto a patterned, metallized polyester film. The pattern is of a transistor gate electrode array. The microdispensing head atomizes the dispersion, generating a liquid spray much like a dual orifice atomizer found on an airbrush.

To create a thick-film electrode, a conductive or dielectric film is applied to a substrate [16]. The film is applied through a mask contacting the substrate and deposited films are obtained by pattern transfer from the mask. 

Additional work on dielectrics includes deposition of silica, PABS (lead aluminum boron silicates), PLZT (lead lanthanum zirconium titanate) and BST (barium strontium titanate) on Si-Ti-Pt wafers (Figure 2). The wafer specimens were patterned with metal electrodes and electronic properties were characterized. 

Dielectric constant measurements were performed with an automatic Hewlett Packard (HP-4270A) capacitance bridge on 2.5 micron low molecular weight SPI-100 films on Al-wafers. A second Al-electrode was sputtered on to the polyimide and patterned with Shipley 1470 photoresist to provide a pattern of dots varying in diameter from. 050 to. 200 inches (1.3-5.1 mm) (see Figure 3). 

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