High-x Dielectrics

A high-fc dielectric is a terminology that is somewhat subjective but has been used frequently in the development of gate dielectrics for CMOS (complementary metal oxide semiconductor applications are discussed next). In this context, the description as a high-x dielectric points to a value of 25-30, being high compared with Si02 (3.9), which had been the traditional material for these applications beforehand (Table 24.1) [5]. Clearly, many 

Other oxides exist that display a large dielectric constant that is orders of magnitude higher than this, such as the ferroelectric BaTiOs or Pb(Zr, Ti)03. Materials with dielectric constant of this order, such as (Ba, Sr)Ti03, are useful as capacitor dielectrics in DRAM (dynamic random access memory) applications. 

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Table 24.1 Examples of high-x dielectric materials with a typical value of their dielectric constant [5,6],...

In our research, we have applied aqueous chemical solution deposition [38,39] to the screening of several candidate high-x dielectric materials such as Zr02, rare... 

The high-frequency dielectric constant is determined by the effects of electronic polarization. An accurate estimate of this property lends confidence to the modeling of the electronic polarization contribution in the piezoelectric and pyroelectric responses. The constant strain dielectric constants (k, dimensionless) are computed from the normal modes of the crystal (see Table 11.1). Comparison of the zero- and high-frequency dielectric constants indicates that electronic polarization accounts for 94% of the total dielectric response. Our calculated value for k (experimental value of 1.85 estimated from the index of refraction of the P-phase of PVDF. ... 

C. Lee and X. Gonze, "Si02-stishovite under high pressure dielectric and dynamical properties, ferroelastic phase transition," accepted for publication in Phys. Rev. B. 

G.-M. Rignanese, X. Gonze, A. Pasquarello, "Ab-Initio Calculations of the Structural, Electronic and Dynamical Properties of High-k Dielectrics", Ed. M. Houssa, Institute of Physics Publishing, 2004, pp 431. 

This is known as a Debye dielectric response, where and 8 are the low and high frequency dielectric constant, and x is the time constant... 

The situation is qualitatively similar in the systems with random site electric dipoles. Here also the competition between fixed and alternating sign interactions defines their phase diagram. However, the nature of these interactions differs essentially from that in magnetic systems. In highly polarizable dielectric lattices with dipole impurities (like Ki cLi cTa03 and Pbi Ge (Te, x <0.1), the impurity ions Li+ and Ge + substitute host ions K+ and Pb + respectively. Former impurity ions are shifted from equilibrium positions in a host lattice as their ionic radii are much smaller than those of the host lattice cations. 

Figure 11.3 Schematic representation of the experimental setup. The following notations have been used BS, beam splitter of the fundamental 775 nm beam shutter 1 and shutter 2, two motorized shutters that block the probe and pump beams, respectively Ml, M2, M3,and M4, high reflection dielectric mirrors at 775 nm, 45° X,/2, aXjl plate Cap2, calcium fluoride plate, used for white light continuum generation M5,...

Bennett, X., Beebe, M., Sparks, C., Gondran, C., Vandervorst, W. (2004) Sputter rate variations in silicon under high-k dielectric films. Applied Surface Science, 257-252,565-568. 

Mashimo, S. (1997), Application high-frequency dielectric measurements of polymers, in Dielectric Spectroscopy of Polymeric Materials—Fundamental and Applications, Runt, J. P. and Fitzgerald, J. X, eds., ACS, Washington, DC, pp. 201-225. 

X (2014) Lanthanum titanium perovskite compound thin film deposition and high frequency dielectric characterization. 

Equation (8.18) is vahd for linear dielectric materials (i.e., polarization is directly proportional to electric field). Ferroelectric materials used in high-X capacitor dielectric materials are nonlinear. Figure 8.34 illustrates the relationships between polarization, electric field, and dielectric constant for a ferroelectric material as given by the following equation ... 

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