共查询到20条相似文献,搜索用时 31 毫秒
1.
Films of (1−x)Pb(Zn1/3Nb2/3)O3-xPb(Zr0.4Ti0.6) O3 (x = 0.6, 40PZN-60PZT) were deposited on Pt/TiO2/ SiO2/Si substrate through spin coating. Using a combination of homogeneous precursor solution preparation and two-step pyrolysis
process, we were able to obtain the 40PZN-60PZT thin films of perovskite phase virtually without pyrochlore phase precipitation
after annealing above 650∘C. But since annealing done at the high temperatures for extended time can cause diffusion of Pt, TiO2 and Si, and precipitation of nonstoichiometric PbO, we adopted 2-step annealing method to circumvent these problems. The
2-step annealed films show dense microstructure than the 1-step films annealed at higher temperature. Furthermore, the root-mean-square
surface roughness of 220 nm thick films which are annealed at 720∘C for 1 min and then annealed at 650∘C for 5 min was found to be 3.9 nm by atomic force microscopy as compared to the 12 nm surface roughness of the film annealed
only at 720∘C for 5 min. The electrical properties of 2-step annealed films are virtually same and those of the 1-step annealed films
annealed at high temperature. The film 2-step annealed at 720∘C for brief 1 min and with subsequent annealing at 650∘C for 5 min showed a saturated hysteresis loop at an applied voltage of 5 V with remanent polarization (P
r) and coercive voltage (V
c) of 25.3 μC/cm2 and 0.66 V respectively. The leakage current density was lower than 10−5A/cm2 at an applied voltage of 5 V. 相似文献
2.
Highly ordered mesoporous TiO2 thin films have been successfully synthesized via a copolymer templating sol-gel route. A configuration transition from hexagonal,
to cubic, and then to a channel-like structure was observed when the copolymer-templated thin film was thermally annealed
from 110 to 450∘C. In the mesoporous TiO2 film annealed at 450∘C, mesopores were merged in a preferential direction, forming a channel-like structure consisting of a semicrystalline (anatase)
framework. These films exhibit excellent optical transparency with transmittance higher than 85% in the visible region. A
blue shift in UV-Vis absorption onset was shown for the mesoporous TiO2 films, indicating a size quantization effect of nanocrystalline titania. 相似文献
3.
ZnNb2O6-TiO2 mixture thin films with multilayer structures were fabricated via a sol-gel spin coating process. TiO2 layers were deposited on the pre-crystallized ZnNb2O6 layers in order to suppress the formation of the ixiolite phase which always forms in the bulk system. The phase constitution
of the thin films, confirmed by X-ray diffraction (XRD), could be controlled by the annealing temperatures, which, in turn,
influenced the dielectric properties of the thin films. TiO2 layers crystallized as the anatase phase and then transformed to the rutile phase at temperatures higher than 725∘C. Dielectric constants of the mixture thin films, measured at 1 MHz with an MIM (metal-insulator-metal) structure, increased
from 27 to 41 with dielectric losses below 0.005 as the annealing temperature increased from 700∘C to 900∘C. The increase in the dielectric constants was understood to originate from the increasing amounts of the rutile phase. Temperature
coefficients of capacitance (TCC) were also measured between 25∘C and 125∘C, which showed a decreasing manner from positive values to negative values with increasing annealing temperatures. When annealed
at 850∘C, the TCC of the thin films could be tuned to be approximately 0 ppm/oC with dielectric constant and dielectric loss of 36 and 0.002, respectively. 相似文献
4.
Fransiska Cecilia Kartawidjaja Zhaohui Zhou John Wang 《Journal of Electroceramics》2006,16(4):425-430
Heterolayered Pb(Zr1 − x
Ti
x
)O3 thin films consisting of alternating PbZr0.7Ti0.3O3 and PbZr0.3Ti0.7O3 layers were successfully deposited via a multistep sol-gel route assisted by spin-coating. These heterolayered PZT films,
when annealed at a temperature in the range of 600–700∘C show (001)/(100) preferred orientation, demonstrate desired ferroelectric and dielectric properties. The most interesting
ferroelectric and dielectric properties were obtained from the six-layered PZT thin film annealed at 650∘C, which exhibits a remanent polarization of 47.7 μC/cm2 and a dielectric permittivity of 1002 at 100 Hz. Reversible polarization constituents a considerably high contribution towards
the ferroelectric hysteresis of the heterolayered PZT films, as shown by studies obtained from C-V and AC measurement. 相似文献
5.
Bo-Yun Jang Beom-Jong Kim Young-Hun Jeong Sahn Nahm Ho-Jung Sun Hwack-Ju Lee 《Journal of Electroceramics》2006,17(2-4):387-391
BaTi4O9 thin films were grown on a Pt/Ti/SiO2/Si substrate using RF magnetron sputtering. A homogeneous BaTi4O9 crystalline phase developed in the films deposited at 550∘C and annealed above 850∘C. When the thickness of the film was reduced, the capacitance density and leakage current density increased. Furthermore,
the dielectric constant was observed to decrease with decreasing film thickness. The BaTi4O9 film with a thickness of 62 nm exhibited excellent dielectric and electrical properties, with a capacitance density of 4.612
fF/μm2 and a dissipation factor of 0.26% at 100 kHz. Similar results were also obtained in the RF frequency range (1–6 GHz). A low
leakage current density of 1.0 × 10−9 A/cm2 was achieved at ± 2 V, as well as small voltage and temperature coefficients of capacitance of 40.05 ppm/V2 and –92.157 ppm/∘C, respectively, at 100 kHz. 相似文献
6.
Wei-Kuo Chia Ying-Chung Chen Cheng-Fu Yang San-Lin Young Wang-Ta Chiang Yu-Tarng Tsai 《Journal of Electroceramics》2006,17(2-4):173-177
Bi4Ti3O12 thin films are deposited on ITO/glass and Pt/Ti/Si(100) substrates by R.F. magnetron sputtering at room temperature. The
films are then heated by a rapid thermal annealing (RTA) process conducted in oxygen atmosphere at temperatures ranging from
550–700∘C. X-ray diffraction examination reveals that the crystalinity of the films grown on Pt/Ti/Si is better than that of the films
grown on ITO/glass under the same fabrication conditions. SEM observation shows that the films grown on Pt/Ti/Si are denser
than those grown on ITO/glass substrates. Interactive diffusion between the Bi4Ti3O12 film and the ITO film increases with the increase of annealing temperature. The optical transmittance of the thin film annealed
at 650∘C is found to be almost 100% when the effect of the ITO film is excluded. The relative dielectric constants, leakage currents
and polarization characteristics of the two films are compared and discussed. 相似文献
7.
Hyun-Suk Kim Il-Doo Kim Ki-Byoung Kim Tae-Soon Yun Jong-Chul Lee Harry L. Tuller Won-Youl Choi Ho-Gi Kim 《Journal of Electroceramics》2006,17(2-4):421-425
We report on high tunablity of Ba0.6Sr0.4TiO3 (BST) thin films realized through the use of atomic layer deposited TiO2 films as a microwave buffer layer between BST and a high resistivity (HR) Si substrate. Coplanar waveguide (CPW) meander-line
phase shifters using BST/TiO2/HR-Si and BST/MgO structures exhibited a differential phase shift of 95∘ and 24.4∘, respectively, at 15 GHz under an electric field of 10 kV/cm. The figure of merit of the phase shifters at 15 GHz was 30.6∘/dB for BST film grown on a TiO2/HR-Si substrate and 12.2∘/dB for BST film grown on a MgO single crystal substrate. These results constitute significant progress in integrating BST
films with conventional silicon technology. 相似文献
8.
G. X. Liu F. K. Shan J. J. Park W. J. Lee G. H. Lee I. S. Kim B. C. Shin S. G. Yoon 《Journal of Electroceramics》2006,17(2-4):145-149
Ga2O3 and Ga2O3-TiO2 (GTO) nano-mixed thin films were prepared by plasma enhanced atomic layer deposition with an alternating supply of reactant
sources, [(CH3)2GaNH2]3, Ti(N(CH3)2)4 and oxygen plasma. The uniform and smooth Ga2O3 and GTO thin films were successfully deposited. Excellent step coverage of these films was obtained by chemisorbed chemical
reactions with oxygen plasma on the surface. The dielectric constant of GTO thin film definitely increased compared to Ga2O3 film, and the leakage currents of GTO films were comparable to Ga2O3 films. The leakage current density of a 40-nm-GTO film annealed at 600∘C was approximately 1×10−7 A/cm2 up to about 600 kV/cm. 相似文献
9.
Wataru Sakamoto Yu-ki Mizutani Naoya Iizawa Toshinobu Yogo Takashi Hayashi Shin-ichi Hirano 《Journal of Electroceramics》2006,17(2-4):293-297
Ferroelectric Si-doped (Bi,Nd)4Ti3O12 thin films have been prepared on Pt/TiOx/SiO2/Si substrates through metal-organic compounds by the chemical solution deposition. The Bi3.25Nd0.75Ti2.9Si0.1O12 (BNTS) precursor films were found to crystallize into the Bi-layered perovskite Bi4Ti3O12 single-phase above 600∘C. The synthesized BNTS films revealed a random orientation having a strong 117 reflection. The BNTS thin films prepared between
600∘C and 700∘C showed well-saturated P-E hysteresis loops with P
r of 13–14 μ C/cm2 and E
c of 100–110 kV/cm at an applied voltage of 5 V. The surface roughness of the BNTS thin films was improved by Si doping compared
with that of undoped Bi3.35Nd0.75Ti3O12 films. 相似文献
10.
We have investigated electrical and structural properties of Pt/Pd/Au ohmic contact on p-type GaN:Mg (2.5 × 1017 cm−3) using Auger electron spectroscopy (AES) and glancing angle x-ray diffraction (GXRD) analysis. It was shown that the specific
contact resistivity improved with increasing annealing temperature. The annealing of the contact at 600∘C for 2 min in flowing N2 atmosphere resulted in a specific contact resistivity of 3.1 × 10−5 Ω cm2. Both GXRD and AES depth profile results show that Ga3Pt5, Ga2Pd5, and Au7Ga2 phases are formed at the interface region between metal and GaN when annealed at temperatures 600∘C. Possible explanation is suggested to describe the annealing dependence of the specific contact resistivity of the Pt/Pd/Au
contacts. 相似文献
11.
ZnGa2O4 thin film phosphors have been synthesized on ITO coated glass and soda-lime glass at a firing temperature of 500∘C and an annealing temperature of 500∘C and 600∘C via a chemical solution method using Zinc acetate dihydrate, Gallium nitrate hydrate and 2-methoxiethanol as a solution.
XRD patterns of the film phosphors synthesized showed the peaks of ZnGa2O4 crystalline phases. AFM surface morphologies of the ZnGa2O4 thin film phosphors revealed marked differences according to an annealing temperature of 500∘C and 600∘C under an annealing atmosphere (3% H2/Ar). On the other hand, the sheet resistance of ZnGa2O4 thin film phosphors, which were measured by four-point probe instrument, was approximately 5.76 Ω /square and 7.86 Ω /square
with annealing temperature, respectively. The ZnGa2O4 thin film phosphors exhibited blue emission spectra with peak wavelength of 434 nm and 436 nm by ultra-violet excitation
around 230 nm. 相似文献
12.
D. Y. Wang Y. Wang J. Y. Dai H. L. W. Chan C. L. Choy 《Journal of Electroceramics》2006,16(4):587-591
Heteroepitaxial Ba0.7Sr0.3TiO3 thin films were grown on (LaAlO3)0.3(Sr2AlTaO6)0.35 (001) (LSAT) and SrTiO3 (001) (STO) single crystal substrates using pulsed laser deposition (PLD). X-ray diffraction characterization revealed a
good crystallinity and a pure perovskite structure for films grown on both LSAT and STO substrates. The in-plane ferroelectric
and dielectric properties of the films were studied using interdigital electrodes (IDE). The film grown on LSAT substrate
exhibited an enhanced in-plane ferroelectricity, including a well-defined P-E hysteresis loop with the remnant polarization
P
r
= 10.5 μC/cm2 and a butterfly-shaped C-V curve. Nevertheless, only a slim hysteresis loop was observed in the film grown on STO substrate. Curie temperature T
c
of the film grown on LSAT substrate was found to be ∼105∘C, which is nearly 70∘C higher than that of the bulk Ba0.7Sr0.3TiO3 ceramics. T
c
of the film grown on STO substrate has almost no change compared to the bulk Ba0.7Sr0.3TiO3 ceramics. The dielectric tunabilities were found to be 64% and 52% at 1 MHz for the films grown on LSAT and STO substrates,
respectively. 相似文献
13.
Ferroelectric Ba0.5Sr0.5TiO3 (BST) films were prepared on Pt/Ti/SiO2/Si substrates by the sol-gel process. The films were spin-coated at 2000 rpm for 30 secs and then pyrolysed for 5 mins at
the temperature of 350∘C. This coating procedure was repeated for 3, 4, 5 and 6 times to obtain BST films with different thicknesses. After coating
the films with the desired repetition times, the films were finally annealed in a conventional furnace at temperatures ranging
from 600∘C to 800∘C with a 50∘C interval in between. The films obtained with an annealing procedure of 750∘C were polycrystalline with the presence of an impurity BaCO3 phase. The capacitance and leakage current were measured and used to extract information on the metal-BST interface. With
the series capacitance model and modified Schottky emission equation, the thickness of the dead layers for Au/BST and Pt/BST
interfaces were calculated to be less than 6 nm and 5 nm, respectively. 相似文献
14.
Yi Wang Lei Sun Ling-Gang Kong Jin-Feng Kang Xing Zhang Ru-Qi Han 《Journal of Electroceramics》2006,16(4):389-391
Effects of Co
x
Ti
1−x
O
2−δ on the sinterability and the ferromagnetism properties of Co
2sO
3/TiO
2 (0.0 < x < 0.06) ceramics are investigated in this paper. It is found that the Co-doped Ti
O
2 ceramics transform from paramagnetism to room-temperature ferromagnetism (RTFM) after hydrogenation. With annealing temperatures
at 600∘
C and 1000∘
C, these as-prepared samples present anatase and rutile structures respectively, which are analyzed with X-ray diffraction
(XRD). After hydrogenation, the relation between temperature variations and the magnetic susceptibility for the hydrogenated
samples were measured under zero-field-cooled and field-cooled conditions by using SQUID magnetometer. And the hysteresis
loops are observed. These ferromagnetism resonance data suggest that the observed RTFM is at least partly due to the Cobalt
nano-particles in our hydrogenated samples. 相似文献
15.
Chul-Ho Park Mi-Sook Won Chul-Su Lee Won-Hyo Cha Young-Gook Son 《Journal of Electroceramics》2006,17(2-4):619-623
PZT thin films and interlayers were fabricated by the radio frequency (r.f.) Magnetron-sputtering from the Pb1.1Zr0.53Ti0.47O3, PbO and TiO2 target. As a result of the XPS depth profile analysis, we can confirm that the substrate temperature affects the oxidation
condition of each element of interlayers and the PZT film. Compared to the PZT/Pt structure, the dielectric and pyroelectric
properties of PZT thin films inserted by interlayers were measured to a relatively high value. In particular, the PZT/PbO
structure had the highest pyroelectric properties (P = 189.4 μC/cm2K; F
D = 12.7×10−6 Pa−1/2; F
V = 0.018 m2/C). 相似文献
16.
Abstract Paraelectric [Pb, La]TiO3 (PLT, La = 28 mol%) thin films were prepared by dc magnetron sputtering using a multi-element metal target. In order to crystallize the as-deposited PLT thin films into the cubic perovskite structure, a heat treatment was applied at annealing temperatures ranging between 450 and 750°C. The electrical measurements such as dielectric properties, polarization-electric field (P-E), and current-voltage (I–V) were investigated with the change of annealing temperature. The dielectric constant and dissipation factor of paraelectric PLT film annealed at 750°C were 1216 and 0.018, respectively. The charge storage density was approximately 12.5 μC/cm2. The leakage current density in PLT film annealed at 650°C was around 0.1 μA/cm2 at the electric field of 0.25 MV/cm. 相似文献
17.
I. H. Kim D. Y. Ku J. H. Ko D. Kim K. S. Lee J.-h. Jeong T. S. Lee B. Cheong Y.-J. Baik W. M. Kim 《Journal of Electroceramics》2006,17(2-4):241-245
To improve the stability of sputter-deposited ZnO:Al (AZO) films at high temperature above 300∘C, an amorphous Zn-Sn-O (ZTO) film was deposited on the top of AZO films as an protective layer by co-sputtering of pure ZnO
and SnO2 targets. Amorphous ZTO films had resistivity in the range from 10−2 to 10−3 Ωcm and were stable up to temperature of 400∘C. Heat treatments of bare AZO films in the atmosphere at 400∘C resulted in a dramatic increase in the resistivity accompanied by substantial decrease in carrier concentration and Hall
mobility. The AZO films covered with the ZTO film showed remarkable improvement in thermal stability for subsequent heat treatments
in the temperature range from 200 to 400∘C in the atmosphere as well as chemical stability in weak acidic solution. X-ray photoelectron spectroscopy analysis showed
that the improvement was attained by ZTO layer acting as diffusion barrier of oxygens and/or water vapors. 相似文献
18.
Anatase TiO2 films were deposited on glass substrates at 50 and 200∘C to investigate the effect of growth temperature on the photocatalytic acitivity of the films. It was observed that the films
grown at 200∘C were composed of columnar crystallites and were more porous than the films grown at 50∘C which had more compact structures. Also, the film crystallinity increased from 75 to 90% if the higher growth temperature
was used. Despite the higher crystallinity, it was observed that for crystallinities between 60 and 90%, the photocatalytic
behavior of the films was more significantly affected by changes in the surface area. 相似文献
19.
High-performance pyroelectric infrared detectors have been fabricated using Lithium tantalite (LiTaO3) thin films deposited on Pt(111)/Ti/SiO2/Si(100) substrates by diol-based sol-gel method and rapid thermal annealing (RTA) technique. The dielectric and pyroelectric
properties of IR detectors of LiTaO3 thin films crystallized by conventional and RTA processes are investigated. Experimental results reveal that the heating
rate will influence strongly on dielectricity and pyroelectricity of LiTaO3 thin films. The voltage responsivities (Rv) measured at 80 Hz increase from 5496 to 8455 V/W and the specific detecivities
(D∗) measured at 300 Hz increase from 1.94 × 108 to 2.38 × 108 cmHz1/2/W with an increase of heating rate from 600 to 1800∘C/min. However, the voltage responsivity and the specific detecivity decrease with heating rate in excess of 1800∘C/min. The results show that the LiTaO3 thin film detector with a heating rate of 1800∘C/min exists both the maximums of voltage responsivity and specific detecivity. 相似文献
20.
T. Yu C. H. Chen Y. K. Lu X. F. Chen W. Zhu R. G. Krishnan 《Journal of Electroceramics》2007,18(1-2):149-154
The sol-gel wet chemical synthesis of dielectric thin films of perovskite Ca1−x
Sr
x
ZrO3 has been studied in detail using different techniques. To the best of our knowledge, it is the first time in the literature
to systemically study the properties of Ca1−x
Sr
x
ZrO3 dielectric thin films in the whole solid solution composition range. Based on X-ray diffraction (XRD), Flourier transform
infrared (FT-IR) reflectivity spectroscopy and atomic force microscope (AFM) data, the mechanisms of Ca1−x
Sr
x
ZrO3 phase transformation and crystallinity have been investigated. The results show that the film annealed at 550 °C is amorphous
with existing of carbonates, while the carbonates and other organics are decomposed at 600 °C and above, and the film is crystallized
into the perovskite phase with increasing annealing temperature. The values of dielectric constant in a range of 16–30 for
Ca1−x
Sr
x
ZrO3 thin films have been obtained. Measured dielectric properties show that those films exhibit stable dielectric properties
nearly independent on the applied electrical field and frequency at room temperature. Based on above data, it can be concluded
that Ca1−x
Sr
x
ZrO3 thin films are a promising candidate system for the high-k microelectronic devices application. 相似文献