Dielectrics, future applications

In conclusion, it has been demonstrated that the pyroelectric properties of polar materials can be compared relatively simply through the measurement of a few key physical parameters (pyroelectric,dielectric and thermal coefficients) and the judicious use of appropriate figures-of-merit. It is essential that the dielectric properties are measured in the frequency range appropriate for device use, and this is typically in the range of a few to 100 Hz. The properties of many pyroelectric ceramics and thin films have been compared and it has been shown that good pyroelectric properties can be obtained from this films manufactured at relatively low temperatures, a fact that bodes well for their future applications in fully-integrated arrays. 

The use of aerosols in plasma technology increases the available spectrum of suitable chemicals considerably. To a certain extent, liquid chemicals, solutions and dispersions can be used in plasma for surface modiflcation with the help of aerosols under atmospheric pressure. Combinations of aerosols and spraying application in dielectrical barrier discharge for the surface treatment of textiles is in the first stage of development and offers potential for future development. Examples of current and future applications are ... 

Zirconyl pyrophosphate, (ZrO)2P207, mp = 2070°C, p = 3.88 g/cc, is stable up to about 1600 C, and calcium orthophosphate, Ca3(P04)2 which melts at 1820°C, can be used for some purposes at temperatures up to 1600°C. The zirconyl compound, which loses P2O5 above 1600°C, has potential use as a low-expansion ceramic, although its strength is rather limited [3]. Up to llOO C the net expansion is <1.7 x 10 C (Table 12.27). Zirconyl pyrophosphate is a good electrical insulator and its dielectric constant is similar to that of alumina [4]. Solid solutions of composition Ca Sr,. Zr4(P04)g and Zr 2-Nx i show almost zero thermal expansion over a considerable temperature range, and are promising materials for future application (see below). 

Of all potential future applications, the most exciting ones are perhaps those associated with making ferroelectric memories which can be addressed by light or with two-dimensional electronic chips. The idea is to store dielectric information from the three-dimensional bulk into electronic configurations of a two-dimensional chip. The high... 

This Section presents a cross-referenced bibliography on the application of dielectric property measurements to thermosetting materials. Our literature search identified almost 200 papers with some relevance to the subject. Of these, we have selected about 70 for inclusion in this section. These papers provide particularly useful application examples, or provide data typical of the particular material or application which future investigators can use for comparisons with their own results. 

With the increase of the degree of integration of microcircuits, the multilevel interconnect technology becomes inevitable for future VLSI manufacture. Polyimide exhibits superior planarity over stepped structures and is expected to be one of the most promising materials for the dielectric insulation of VLSI s. However, since the smallest via holes so far achieved by wet etching is 3 pm (1), the formation of fine via holes by a dry etch process is needed for the application of polyimide to VLSI having fine metal wiring. 

Layers Typical materials for which CMP processes originally have been developed for microelectronic applications include various types of silicon dioxide such as thermal oxide, TEOS, HDP, BPSG, and other B- or P-doped oxide films. These films are used for various isolation purposes including interlevel dielectric (ILD), intermetal dielectric (IMD), or shallow trench isolation (STI). In addition, n- or p-doped poly-Si, which is a semiconducting material used as capacitor electrode material for DRAMS or gate electrode for MOS applications (CMOS as well as power MOS devices), also has to be polished. Metals for which CMP processes have emerged over the last 10-15 years are W for vertical interconnects (vias) and most importantly Cu as a low-resistivity replacement for aluminum interconnects, employed in the damascene or dual-damascene processing scheme. Other metals that are required for future nonvolatile memories are noble metals like Pt or Ir for which CMP processes have been explored. 

In addition to new resists, future generations of devices will require improved dielectrics that can be deposited at low temperatures and provide process flexibility. Again, organosilicon polymers have promise for this application. In this chapter, the chemistry and processes for both of these areas will be reviewed. 

Commercial submicron BT particles were modified for the study of the preferred crystal phase relationship to the corresponding dielectric properties. The results reveal that the crystal phase of the BT particles in the nanometer size range relates to the impurities incorporated in the BT crystal lattice. The responsible impurity has been identified as hydroxyls. BT is considered to meet the demands for current and future capacitor applications by modifying submicron BT particles. 

Low-fc dielectrics are important as packaging materials for future developments of microelectronics. Thin-hlm dense silica has always been the material of choice for this application. Their low dielectric constants, plus their good thermal and mechanical stability and hydrophobicity, suggest the potential utility of mesoporous organosilica films as low-fc layers in microelectronics.[272,309]... 

---