Fabrication of planar interdigitated electrodes for dielectric spectroscopy of thin films
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Date
2014-09-17
Authors
shenouda, mina
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Abstract
The dielectric properties of polymeric thin films (100-200 nm) are hard to
measure with the standard approaches as the samples aren't free standing necessitating
a supporting substrate. Consequently, a planar interdigitated sample holder
has been designed to hold the thin film where the polymeric capacitance was derived
from the passing fringing fields.
The electrodes were fabricated by creating 120 nm trenches in a SiO2/Si wafer; 20
nm Cr was deposited as an adhesion layer prior to the deposition of Cu by thermal
evaporation. The electrical measurements were implemented using HP 4294A and a
probe station.
Devices of 20 to 70 fingers were measured and the results were compared to the
analytical and finite element simulation. At 10 KHz, the total measured capacitance
of a 20-finger device was about 8 pF with 3 % represented the polymeric
contribution. The measurements differed from the calculations or finite modeling
results by about 12%.
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Keywords
thin, films, dielectric, interdigitated, spectroscopy, electrodes