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Chapter V Dielectric Study of ……
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Dielectric study of NLO material is very important because the
operation of electro-optic devices is based on the Pockel’s effect in which the
change in the dielectric constant is a linear function of applied field [40].
Microelectronics industry requires replacement of dielectric materials in multi-
level inter connect structures with new low dielectric constant materials as an
interlayer dielectric (ILD), which surrounds and insulates interconnecting
wirings. Lowering the dielectric constants of the ILD decreases the RC delay,
lowers the power consumptions and reduces the “crosstalk” between the
nearby interconnects [41]. Therefore, many attempts were made to study the
reduction dielectric constant values of the doped systems.
The electrical characterizations of L-histidine doped KDP and ADP has
been reported by Meena and Mahadevan [42]. It has been found that the σdc
(d.c conductivity), εr (dielectric constant), σac (a.c conductivity) and
tanδ(dielectric loss) values increase with temperature and decrease with
impurity concentration in KDP and ADP crystals along both a- and c-
directions. The values have been found more for ADP crystals than that for
KDP crystals. The electrical conductivity of KDP type crystals can be
determined by the proton transport within the framework of hydrogen bonds
[43]. Two mechanisms can be proposed, which are, (1) considering similarity
to the conductivity mechanism in ice having hydrogen bonds [43] and (2)
considering conductivity associated with the incorporation into the crystal
lattice of impurities having different valences and the formation of
corresponding defects in the ionic crystals [44]. It has been assumed that the
conductivity of ice is obtained by the simultaneous presence of positive and
negative ions and orientational defects – vacant hydrogen bonds (L-defects)
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