Abstract: In this study, BiFeO3 (BFO) epitaxial film was deposited on SrRuO3 (100)/SrTiO3 (100) substrates
using pulsed laser deposition (PLD). Phase pure BFO thin film was obtained. Introducing a mask
between the target and substrate in PLD improved the surface roughness from 47.8 nm (RMS,
without mask) to 7.7 nm (RMS, with mask). The composition and electrical properties of BFO thin
film were assessed after annealing for 1 h in Ar, N2, or O2 atmosphere at 600°C. The P-E hysteresis
properties improved only in the O2 atmosphere. After annealing under O2 atmosphere, the leakage
current decreased from 6.1 × 10-2 A/cm to 2.9 × 10-2 A/cm at 200 kV/cm, as in the other annealing
atmospheres, but 2Pr increased from 35 BC/cm2 to 50 BC/cm2.
Abstract: The electrical properties of perovskite-based ferroelectric films were improved by ion modification using
rare-earth cations. Thin films of rare-earth-modified lead zirconate titanate [Pb(Zr,Ti)O3] were fabricated on
(111)Pt/Ti/SiO2/(100)Si substrates by a chemical solution deposition technique. The substitution of volatile
cations in the simple-perovskite oxides, such as Pb2+ in Pb(Zr,Ti)O3 films, enhanced the insulating properties
of the film. The crystal anisotropy of the Pb(Zr,Ti)O3 film could be controlled by varying the species and the
amount of replacing cations to enhance the spontaneous polarization. Thus, ion modification using Dy3+
cation could enhance the remanent polarization of Pb(Zr,Ti)O3 film consequently.
Abstract: Pb(Zr0.05Ti0.95)O3/(La,Sr)CoO3 thin films were prepared by pulsed laser deposition (PLD) on
SrTiO3(001) substrates. Phase transition behavior of Pb(Zr0.05Ti0.95)O3 (PZT) was investigated using
high temperature X-ray diffraction (HT-XRD) and high-temperature electrical measurement. The
phase transition temperature of PZT thin film is larger than bulk one. In 100 and 200nm-thickness
epitaxial PZT thin films, the phase transition temperatures obtained from X-ray diffraction
measurement and electrical property measurement are in good agreement.
Abstract: Epitaxial LiTaO3 thin films were deposited on epitaxial Pt(111)/Al2O3(001) and Al2O3(001)
substrates by metal organic chemical vapor deposition using LiTa(OC2H5)4(OC2H4OCH3)2 and
Li(DPM) precursors. The full-width at half-maximum of the rocking curve of LiTaO3 thin films were
respectively 0.29° on Al2O3(001) substrates and 0.98° on epitaxial Pt(111)/Al2O3(001). Electrical
measurements showed that the remanent polarization and coercive field of the films were 2Pr=76
μC/cm2 and E
=130 kV/cm, respectively. The leakage current density was 10-6–10-8 A/cm2 at 120
kV/cm. Refractive indices n measured at 632.8 nm were measured respectively as 2.15 on Al2O3(001)
and 2.14 on Pt(111)/Al2O3(001).
Abstract: Photovoltaic lead lanthanum zirconate titanate films in a layered structure of different
crystallographic orientations are fabricated by an optimized metalorganic deposition method. Such
films of (001) orientation exhibit a photovoltaic electrical power of approximately 20 times higher
than that of random films. The anisotropic optical properties of the oriented films, including dark
conductivity, photoconductivity and photovoltaic tensor surfaces, are obtained quantitatively.
These results show that the photovoltaic output current and power of the oriented films are highly
improved to be equal to those of semiconductors and suitable for application in the optical sensor of
Abstract: Changes of residual stress and electrical properties were examined in (001)-oriented and
(111)-oriented Pb(Zr0.5Ti0.5)O3 (PZT) thin films deposited on a buffered-Si substrate with a buffer and
bottom electrode layer of a (La,Sr)CoO3(LSCO). A (001)-epitaxial PZT film was prepared on
LSCO/CeO2 /Zr0.85Y0.15O1.93(YSZ)/Si. In addition, a (111)-oriented PZT film was prepared on
LSCO/SrTiO3(ST) /Mn0.24Zn0.09Fe2.67O4(MZF)/YSZ/Si. The residual tensile stress in (001)-PZT thin
films decreased from 2.92 to 1.98 GPa and the remanent polarization increased from 7.5 to 41.7
@C/cm2 as the LSCO thickness increased. In (111)-PZT, the residual tensile stress decreased from
1.72 to 0.95 GPa and remanent polarization increased from 9.5 to 26.7 @C/cm2. The residual tensile
stress of (111)-PZT was less than that of (001)-PZT. The remanent polarization in the 80 nm
(111)-PZT was greater than that of the 60 nm (001)-PZT. In the 700-nm-thick PZT, the remanent
polarization in (001)-PZT was greater than that in (111)-PZT.
Abstract: The influence of a rare earth oxide/yttria-stabilized zirconia (YSZ) double buffer layer structure on
the orientation of a perovskite thin film was investigated on (100) silicon substrates. A calcium
titanate perovskite film with a mixture of (110) and (100) orientation was grown epitaxially on a
YSZ buffer layer. Since rare earth oxides have almost the same chemical nature and different lattice
parameters, it is anticipated that the lattice parameter of the buffer layer can be controlled by
changing the rare earth element. An (100) oriented epitaxial calcium titanate film was obtained by
changing the composition of rare earth oxides on the YSZ/Si substrate.
Abstract: The Y0.5Yb0.5MnO3 ferroelectrics/HfO2 stacking layer was constructed on Si(100) substrate through
the chemical solution deposition. The HfO2 insulating layer crystallized on Si(100) substrates
consisted of uniform grains and had smooth surface. The Y0.5Yb0.5MnO3 film prepared on the HfO2
insulator layer had preferred orientation along c-axis. The Y0.5Yb0.5MnO3 film consisted of uniform
grains and had smooth surface. The clockwise C-V hysteresis induced by ferroelectric polarization
switching was observed in the MFIS structure. The memory window of the MFIS structure was
about 2 V and the retention time was over 105 s.
Abstract: BaTiO3 films with thickness of ~1 2m were prepared by chemical solution deposition on
LaNiO3/Pt/TiOx/SiO2/Si substrate with a thin highly (100)-oriented and high crystallinity BaTiO3
thin film (~140 nm) as a buffer layer. The BaTiO3 films prepared by using a 0.5 mol/L solution have
high crystallinity and still show (100) preferred orientation. The electrical properties of the
(100)-oriented BaTiO3 films prepared by this process have been studied. A dielectric constant of
~910 and a loss tangent of ~3.5% (1 kHz) were obtained. The remanent polarization (2 Pr) and
coercive field (2 Ec) are 4.0 μC/cm2 and 35 kV/cm, respectively.
Abstract: Epitaxially grown (Ba,Sr)TiO3 thin films were prepared on platinum-coated silicon substrate by
sol-gel method using a (Ba,Sr)TiO3 sol derived from Ba(CH3COO)2, Sr(CH3COO)2 and
Ti(O-i-C3H7)4. The morphology of the films was found to depend on the annealing condition. A
columnar structure was obtained for (Ba,Sr)TiO3 thin film by annealing at 800 °C and a columnar
grain was found to be single crystal by transmission electron microscope (TEM). The columnar
grown film exhibits a preferred (111) orientation that follows the (111) orientation of Pt substrate.
Measurement of the C-V in MFM was configured in order to demonstrate good dielectric properties.
Obtained films showed high voltage tunability.