Abstract— In this paper, the propagation characteristics of an
enhanced-thickness magnetic nanoparticle thin film are
investigated on high resistivity silicon substrate (10,000 ohm-cm)
for the first time up to 60 GHz. Contrary to other thin films, this
nanoparticle thin film can achieve a thickness up to several
hundred nanometers, even to micron. The enhanced thickness of
this thin film is achieved by repeated coating of CoFe
2
O
4
and poly,
thus providing the thin film with the high permeability capable of
potential practical wireless applications. Finite Ground Coplanar
(FGC) waveguides are fabricated and characterized on silicon
with the novel thin film. The measured attenuation and effective
dielectric/magnetic constant are reported. Results show that the
FGC waveguides with the thin film feature a lower attenuation
compared to those on silicon for frequencies higher than 18 GHz.
The extracted relative permeability has a value of 68 by matching
of the effective dielectric/magnetic constant between simulation
and measurement.
Index Terms— Magnetic thin film, Nanoparticle, Coplanar
waveguide, high-permeability materials, FGC
I. INTRODUCTION
riven by the demand of monolithic microwave
integration, magnetic nanoparticle thin films [1]-[2] with
high
r
μ developed on CMOS compatible process, find
numerous applications in high-speed wireless communication
systems, (e.g. integrated inductors [3]-[5]), integrated
electromagnetic noise countermeasures [6], and sensing [7]-[8].
In the traditional integrated spiral inductors with a good low
quality factor, it is hard to achieve large inductance values even
with an increased number of turns. As a result, a large area of
the chip is occupied by inductors. Magnetic thin films,
meanwhile, with high permeability, have the potential to
provide compact integrated inductors with high inductance and
good quality factors due to the reduced loss and the fact that the
flux is constrained in the thin film instead of the whole
substrate.
Fig. 1. The SEM picture of the enhanced-thickness magnetic nanoparticle thin
film.
For integrated electromagnetic noise countermeasure
applications, magnetic thin films provide a large attenuation in
the desired stop band, while sustaining the insertion loss in the
passband. For sensing applications, the large permeability of
the thin film enhances its sensitivity.
Novel Enhanced-Thickness Magnetic Nanoparticle Thin-Films
for System-On-Chip (SOC) Wireless Applications
Yuan Li
1
, Hyungie Doo
2
, Bo Pan
1
, Manos M. Tentzeris
1
, Z. John Zhang
2
, and John Papapolymerou
1
1. Georgia Electronic Design Center, School of Electrical & Computer Engineering, Georgia Institute of
Technology, Atlanta, GA 30332;
2. School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
D
Fig. 2. Schematic of the thin film coating process.
978-1-4244-1780-3/08/$25.00 © 2008 IEEE 97
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