The dielectric loss of parallel-plate Pt/Bi1.5MgNb1.5O7 (BMN)/Pt thin film varactors were investigated. The effects of four extrinsic loss mechanisms were discussed. The results showed that the loss mechanism of conduction electrons, local polar regions, and universal relaxation contributed little to the BMN thin film varactors. However, the losses owing to charged defects were found to be the mainly loss mechanism at low frequency (below 1 MHz). The experimental data were in good agreement with the ω1/3 power law. We studied the effect of charged defects mechanism using BMN thin films annealing in different air conditions. It is clearly seen that the charged defects were associated with oxygen vacancies. In the frequency range 100 MHz-6 GHz, the losses of BMN thin film varactors did no fit the charged defects mechanism very well, which were due to the additional losses induced by electrodes, parasitic capacitances, and test equipments. The study of extrinsic loss mechanisms provided useful information for the deposition, varactor design, and the dielectric properties optimization of the BMN thin films.

1.
J.
Nath
,
D.
Ghosh
,
J.
Maria
,
A. I.
Kingon
,
W.
Fathebab
,
F.
Franzon
, and
M. B.
Steer
, “
An electronically tunable microstrip bandpass filter using thin-film barium-strontium-titanate (BST) varactors
,”
IEEE Trans. Microwave Theory Tech.
53
(
9
),
2707
2711
(
2005
).
2.
S.
Courreges
,
B.
Lacroix
,
A.
Amadjikpe
,
S.
Philips
,
Z.
Zhao
,
K.
Choi
,
A.
Hunt
, and
J.
Papapolymerou
, “
Back-to-back tunable ferroelectric resonator filters on flexible organic substrates
,”
IEEE Trans. Ultrason. Ferroelectr. Freq. Control
57
(
6
),
1267
1275
(
2010
).
3.
S.
Sheng
and
C. K.
Ong
, “
Coupled microstrip line microwave phase shifter using ferroelectric thin film varactors
,”
J. Appl. Phys.
111
,
044506
(
2012
).
4.
F. A.
Miranda
,
C. H.
Mueller
,
F. W.
Van Keuls
, and
R. R.
Romanofsky
, “
BaxSr1-xTiO3 thin film ferroelectric-coupled microstripline phase shifters with reduced device hysteresis
,”
J. Am. Ceram. Soc.
91
(
6
),
1864
1868
(
2008
).
5.
X. Y.
Zhang
,
P.
Wang
,
S.
Sheng
,
F.
Xu
, and
C. K.
Ong
, “
Ferroelectric BaxSr1-xTiO3 thin-film varactors with parallel plate and interdigital electrodes for microwave applications
,”
J. Appl. Phys.
104
,
124110
(
2008
).
6.
A.
Vorobiev
,
P.
Rundqvist
,
K.
Khamchane
, and
S.
Gevorgian
, “
Silicon substrate integrated high Q-factor parallel-plate ferroelectric varactors for microwave/millimeterwave applications
,”
Appl. Phys. Lett.
83
,
3144
3146
(
2003
).
7.
B.
Acikel
,
T. R.
Taylor
,
P. J.
Hansen
,
J. S.
Speck
, and
R. A.
York
, “
A new high performance phase shifter using BaxSr1-xTiO3 thin films
,”
IEEE Microw. Wirel. Compon. Lett.
12
,
237
239
(
2002
).
8.
I. D.
Kim
,
H. L.
Tuller
,
H. S.
Kim
, and
J. S.
Park
, “
High tunability (Ba,Sr)TiO3 thin films grown on atomic layer deposited TiO2 and Ta2O5 buffer layers
,”
Appl. Phys. Lett.
85
,
4705
4707
(
2004
).
9.
M. W.
Cole
,
W. D.
Nothwang
,
J. D.
Demaree
, and
S.
Hirsch
, “
Integration of Ba1-xSrxTiO3-based active thin films with silicon-compatible materials and process science protocols to enable affordable on-the-move communications technologies
,”
J. Appl. Phys.
98
,
024507
(
2005
).
10.
L.
Yan
,
L. B.
Kong
,
L. F.
Chen
,
K. B.
Chong
, and
C. Y.
Tan
, “
Ba0.5Sr0.5TiO3-Bi1.5Zn1.0Nb1.5O7 composite thin films with promising microwave dielectric properties for microwave device applications
,”
Appl. Phys. Lett.
85
,
3522
3524
(
2004
).
11.
R. G.
Li
,
S. W.
Jiang
,
L. B.
Gao
,
L. Y.
Wang
, and
Y. R.
Li
, “
Tunable capacitors employing BZN/BST thin films for RF applications
,”
IEEE Trans. Ultrason. Ferroelectr. Freq. Control
58
(
6
),
1140
1144
(
2011
).
12.
L. H.
Yang
,
G. S.
Wang
,
X. L.
Dong
, and
D.
Remiens
, “
Improved dielectric properties of Bi1.5Zn1.0Nb1.5O7/(111)-oriented Ba0.6Sr0.4TiO3 bilayered films for tunable microwave applications
,”
J. Am. Ceram. Soc.
93
(
5
)
1215
1217
(
2010
).
13.
L. B.
Gao
,
S. W.
Jiang
,
R. G.
Li
,
B.
Li
, and
Y. R.
Li
, “
Structure and dielectric properties of sputtered bismuth magnesium niobate thin films
,”
Thin Solid Films
520
,
6295
6298
(
2012
).
14.
S. W.
Jiang
,
Y. R.
Li
,
R. G.
Li
,
N. D.
Xiong
,
L. F.
Tan
,
X. Z.
Liu
, and
B. W.
Tao
, “
Dielectric properties and tunability of cubic pyrochlore Bi1.5MgNb1.5O7 thin films
,”
Appl. Phys. Lett.
94
,
162908
(
2009
).
15.
A. K.
Jonscher
, “
Low-loss dielectrics
,”
J. Mater. Sci.
34
,
3071
3082
(
1999
).
16.
A. K.
Jonscher
, “
Dielectric relaxation in solids
,”
J. Phys. D: Appl. Phys.
32
,
R57
R70
(
1999
).
17.
N. K.
Pervez
, “
Investigation of loss mechanisms in thin film barium strontium titanate capacitors
,” Ph.D. dissertation (
University of California
Santa Barbara,
2006
).
18.
O. G.
Vendik
,
L. T.
Ter-Martirosyan
, and
S. P.
Zubko
, “
Microwave losses in incipient ferroelectrics as functions of the temperature and the biasing field
,”
J. Appl. Phys.
84
,
993
998
(
1998
).
19.
J.
Petzelt
,
T.
Ostapchuk
,
I.
Gregora
,
I.
Rychetsk
,
S.
Hoffmann-Eifert
,
A. V.
Pronin
,
Y.
Yuzyuk
,
B. P.
Gorshunov
,
S.
Kamba
,
V.
Bovtun
,
J.
Pokorn
,
M.
Savinov
,
V.
Porokhonskyy
,
D.
Rafaja
,
P.
Vanek
,
A.
Almeida
,
M. R.
Chaves
,
A. A.
Volkov
,
M.
Dressel
, and
R.
Waster
, “
Dielectric, infrared, and Raman response of undoped SrTiO3 ceramics: Evidence of polar grain boundaries
,”
Phys. Rev. B
64
,
184111
(
2001
).
20.
A. A.
Sirenko
,
I. A.
Akimov
,
J. R.
Fox
,
A. M.
Clark
,
H. C.
Li
,
W. D.
Si
, and
X. X.
Xi
, “
Observation of the first-order Raman scattering in SrTiO3 thin films
,”
Phys. Rev. Lett.
82
(
22
),
4500
4503
(
1999
).
21.
Q. Y.
Qiu
and
V.
Nagarajan
, “
Film thickness versus misfit strain phase diagrams for epitaxial PbTiO3 ultrathin ferroelectric films
,”
Phys. Rev. B
78
,
064117
(
2008
).
22.
E.
Schloman
, “
Dielectric losses in ionic crystals with disordered change distributions
,”
Phys. Rev.
135
,
A413
419
(
1964
).
23.
O. G.
Vendik
and
L. M.
Platonova
, “
Effect of changed lattice imperfections on the dielectric properties of materials
,”
Sov. Phys. Solid State
13
,
1353
1359
(
1971
).
24.
B. M.
Garin
, “
One-phonon dielectric losses by excitation of sound
,”
Sov. Phys. Solid State
32
,
1917
1920
(
1990
).
25.
O. G.
Vendik
and
A. N.
Rogachev
, “
Electrostriction mechanism of microwave losses in a ferroelectric film and experimental confirmation
,”
Tech. Phys. Lett.
25
,
702
704
(
1999
).
26.
A.
Vorobiev
,
P.
Rundqvist
,
K.
Khamchane
, and
S.
Gevorgian
, “
Microwave loss mechanisms in Ba0.25Sr0.75TiO3 thin film varactors
,”
J. Appl. Phys.
96
,
4642
4649
(
2004
).
27.
O. G.
Vendik
and
L. T.
Ter-Martirosyan
, “
Influence of charged defects on the dielectric response of incipient ferroelectrics
,”
J. Appl. Phys.
87
,
1435
1439
(
2000
).
You do not currently have access to this content.