共查询到20条相似文献,搜索用时 31 毫秒
1.
Jeffrey S Cross Seung-Hyun Kim Satoshi Wada Abhijit Chatterjee 《Science and Technology of Advanced Materials》2010,11(4)
Ferroelectric random access memory (FeRAM) has been in mass production for over 15 years. Higher polarization ferroelectric materials are needed for future devices which can operate above about 100 °C. With this goal in mind, co-doping of thin Pb(Zr40,Ti60)O3 (PZT) films with 1 at.% Bi and 1 at.% Fe was examined in order to enhance the ferroelectric properties as well as characterize the doped material. The XRD patterns of PZT-5%
BiFeO3 (BF) and PZT 140-nm thick films showed (111) orientation on (111) platinized Si wafers and a 30 °C increase in the tetragonal to cubic phase transition temperature, often called the Curie temperature, from 350 to 380 °C with co-doping, indicating that Bi and Fe are substituting into the PZT lattice. Raman spectra revealed decreased band intensity with Bi and Fe co-doping of PZT compared to PZT. Polarization hysteresis loops show similar values of remanent polarization, but square-shaped voltage pulse-measured net polarization values of PZT-BF were higher and showed higher endurance to repeated cycling up to 1010 cycles. It is proposed that Bi and Fe are both in the +3 oxidation state and substituting into the perovskite A and B sites, respectively. Substitution of Bi and Fe into the PZT lattice likely creates defect dipoles, which increase the net polarization when measured by the short voltage pulse positive-up-negative-down (PUND) method. 相似文献
2.
《Materials Science and Engineering: B》2001,79(1):86-89
Relationship between the crystallographic orientation and the electrical properties of the Pb(Zr,Ti)O3, (PZT) thin films prepared by rf magnetron sputtering was investigated. The PZT films were deposited at 150, 250 or 340°C and, followed by rapid thermal annealing (RTA). It was found that the crystallographic orientation of the PZT films could be controlled only by the deposition temperature and the ferroelectric properties were dependent upon the orientation of the films. It was suggested that the difference in the atomic mobility at the substrate surface during deposition was closely related to the film orientation. The films with (111) orientation showed relatively high capacitance and the remanant polarization values. 相似文献
3.
B. T. Liu F. Li C. S. Cheng D. Q. Wu X. B. Yan F. Bian Z. Yan Q. X. Zhao X. Y. Zhang 《Journal of Materials Science》2007,42(16):6956-6960
LaNiO3 (LNO) film grown at room temperature (RT) by RF magnetron sputtering is used as the electrode for integrating LaNiO3/PbZr0.4Ti0.6O3/LaNiO3 (LNO/PZT/LNO) capacitor on SrTiO3 (STO) substrate. For comparison, LNO film grown at 250 °C is also used as the electrode of PZT capacitor. Reflection high
energy electron diffraction (RHEED) technique is used to characterize the LNO film, it is found that LNO film prepared at
250 °C is epitaxial although no diffraction pattern is found for RT as-grown LNO. Ferroelectric properties of PZT films strongly
depend on the LNO bottom electrodes. The remanent polarization (P
r) and coercive voltage (V
c), measured at 5 V, for the capacitors with LNO bottom electrodes prepared at RT and 250 °C, are 20 and 37 μC/cm2, 1.67 and 1.95 V, respectively. No obvious degradation of polarization for PZT capacitors with RT as-grown LNO electrodes
can be found. Room temperature as-grown LNO as both bottom and top electrodes to fabricate ferroelectric capacitors can save
2/3 thermal budgets, which may pay a way to decrease the potential challenges of devices resulting from the oxidation, interdiffusion
or reactions during integrating ferroelectric capacitors with Si technologies. 相似文献
4.
M. Khodaei S. A. Seyyed Ebrahimi Yong Jun Park Seungwoo Song Hyun Myung Jang Junwoo Son Sunggi Baik 《Journal of Materials Science: Materials in Electronics》2013,24(10):3736-3743
Perovskite Pb(Zr0.52Ti0.48)O3 (PZT) thin film with perfect (111)-orientation was achieved on CoFe2O4 seeded-Pt(111)/Ti/SiO2/Si substrate by pulsed laser deposition technique using target with limited excess Pb. Pyrochlore phase formation was suppressed on Pt by CoFe2O4 nano-seed layer (~7 nm), and perovskite PZT was achieved at temperature as low as 550 °C. CoFe2O4 seed layer that has perfect (111)-orientation acts as a promoter for perfectly (111)-orientated growth of PZT. PZT film grown at 600 °C has higher degree of crystalline orientation, lower surface roughness, and compacted microstructure in comparison to the film grown at 550 °C. The PZT film has a nano-size grain-feature structure with grain size of about 40–60 nm. Perovskite formation was also confirmed by ferroelectric measurement. The ferroelectric properties of PZT film grown at 600 °C is higher than that grown at 550 °C which could be attributed to the enhancement of the crystalline orientation, crystallinity, and microstructure of the film. 相似文献
5.
Pb(Zr0.53Ti0.47)O3 (PZT) thin films were prepared on Pt/Ti/SiO2/Si substrate by sol–gel method. The effect of annealing temperature on microstructure, ferroelectric and dielectric properties
of PZT films was investigated. When the films were annealed at 550–850 °C, the single-phase PZT films were obtained. PZT films
annealed at 650–750 °C had better dielectric and ferroelectric properties. The sandwich composites with epoxy resin/PZT film
with substrate/epoxy resin were prepared. The annealing temperature of PZT films influenced their damping properties, and
the epoxy-based composites embedded with PZT film annealed at 700 °C had the largest damping loss factor of 0.923. 相似文献
6.
M. Khodaei Daehee Seol S. A. Seyyed Ebrahimi Yong Jun Park Hosung Seo Yunseok Kim Sunggi Baik 《Journal of Materials Science: Materials in Electronics》2014,25(4):1696-1702
Perfect (111)-oriented Pb(ZrxTi1?x)O3 (PZT) thin films were grown on cobalt ferrite buffered Pt(111)/Ti/SiO2/Si substrate by pulsed laser deposition method using various targets with different Zr/Ti ratios ranging from 30/70 to 70/30. The results of X-ray diffraction analyses indicated that the composition of morphotropic phase boundary in the present PZT films is same as the bulk PZT (Zr/Ti = 52/48). The effect of Zr/Ti ratio of the PZT films was investigated by the ferroelectric domain structure and the piezoelectric characteristics of the films by piezoresponse force microscopy, as well as polarization measurement. The results revealed that the present tetragonal PZT film has a higher ferroelectric domain switching than rhombohedral one and the film with composition of Zr/Ti = 52/48 showed relatively high value of squareness of P–E loop and Ec as well as high piezoresponse. 相似文献
7.
Hitoshi Morioka Keisuke Saito Shintaro Yokoyama Takahiro Oikawa Toshiyuki Kurosawa Hiroshi Funakubo 《Journal of Materials Science》2009,44(19):5318-5324
Epitaxial Pb(Zr0.35Ti0.65)O3 (PZT) thin films with tetragonal symmetry and thicknesses ranging from 45 to 230 nm were grown at 540 °C on SrRuO3-coated (001)SrTiO3 substrates by pulse-injected metalorganic chemical vapor deposition. The effect of the film thickness on the ferroelectric
domain structure and the dielectric and ferroelectric properties were systematically investigated. Domain structure analysis
of epitaxial PZT films was accomplished with high-resolution X-ray diffraction reciprocal space mapping and high-resolution
transmission electron microscopy. Fully polar-axis (c-axis)-oriented epitaxial PZT thin films with high ferroelectric polarization values [e.g., remanent polarization (P
r) ~ 90 μC/cm2] were observed for film thicknesses below 70 nm. Films thicker than 70 nm had a c/a/c/a polydomain structure and the relative volume fraction of c-domains monotonously decreased to about 72% on increasing the film thickness up to 230 nm , and finally P
r diminished to about 64 μC/cm2 for the 230-nm-thick epitaxial film. These polarization values were in good agreement with the estimated values taking into
account the volume fraction of the c-axis-oriented domains while assuming a negligible contribution of 90° domain reorientation caused by an externally applied
electric field. 相似文献
8.
《Materials Letters》2004,58(12-13):1885-1888
Barium metaplumbate (BaPbO3, BPO) thin films were prepared on Pt/Ti/SiO2/Si substrates by a sol–gel method and a rapid thermal annealing (RTA) process. X-ray diffraction (XRD) was used to characterize the crystalline structure of the resultant films. It was shown that the formation of perovskite BPO greatly depends on the lead concentration and the final annealing temperature. In terms of the semi-quantitative energy dispersion spectrum (EDS) analysis, the ratio of Pb/Ba in the BPO ceramic films increases as the final heating temperature increases. Using BPO as buffer layers, PZT thin films with a pure perovskite structure were grown at a very low temperature of 500 °C by the sol–gel technique and the RTA process. The remanent polarization of Pt/PZT/BPO/Pt ferroelectric capacitors is about 17 μC/cm2 at an applied voltage of 3 V. 相似文献
9.
Yong Suk Yang Hye Yong Chu Seong Hyun Kim Sang Chul Lim Jae Bon Koo Jung Hun Lee Chan Hoe Ku Jeong-Ik Lee Lee-Mi Do Chi Sun Hwang Sang-He Ko Park Gi Heon Kim Sung Mook Jung 《Thin solid films》2007,515(19):7688-7691
Organic electronic devices using a pentacene have improved importantly in the last several years. We fabricated pentacene organic thin-film transistors (OTFTs) with dielectric SiO2 and ferroelectric Pb(Zr0.3,Ti0.7)O3 (PZT) gate insulators. The organic devices using SiO2 and PZT films had the field-effect mobility of approximately 0.1 and 0.004 cm2/V s, respectively. The drain current in the transfer curve of pentacene/PZT transistors showed a hysteresis behavior originated in a ferroelectric polarization switching. In order to investigate the polarization effect of PZT gate dielectrics in a logic circuit, the simple voltage inverter using SiO2 and PZT films was fabricated and measured by an output-input measurement. The gain of inverter at the poling-down state was approximately 7.2 and it was three times larger than the value measured at the poling-up state. 相似文献
10.
Magnetoelectric (ME) Ni/Pb(Zr0.52Ti0.48)O3 bilayers have been prepared by hydrothermal method. The structure and ferroelectric properties of the Pb(Zr0.52Ti0.48)O3 (PZT) thin films prepared at various hydrothermal temperatures are characterized by X-ray diffraction and ferroelectric testing. With the hydrothermal temperature increasing the grain size of the PZT thin films gradually decreases leading to a gradual increase of the coercive field and a decrease of the remnant polarization of the Ni/PZT bilayers. The ME voltage coefficient of the Ni/PZT bilayers gradually decreases as hydrothermal temperature increases. The large ME coefficient makes these Ni/PZT bilayers possible for applications in multifunctional devices such as electromagnetic sensor, transducers and microwave devices. 相似文献
11.
J.-H. Park S. H. Yoon D. Shen S.-Y. Choe Y. S. Yoon M. Park D.-J. Kim 《Journal of Materials Science: Materials in Electronics》2009,20(4):366-373
Tetragonal lead zirconate titanate (PZT) films with different orientations and 200 nm film thicknesses were prepared on platinized
silicon substrates. Types of substrate and control of thermal processes, such as layer-by-layer and one-crystallization heat
treatments, result in highly (111) or (100)-oriented PZT films. The piezoelectric, dielectric, and ferroelectric properties
of polycrystalline PZT films have been investigated as a function of preferred orientation. The property difference between
(111) and (100)-oriented films appears to be induced by the effect of ferroelastic domain existence (90° domain in tetragonal
composition). From a modified phenomenological equation, the higher electrostrictive coefficient value of 5.6 × 10−2 m4/C2 for (100)-oriented PZT may be responsible for the larger piezoelectric coefficients in (100)-oriented polycrystalline PZT
films of 44 pm/V in comparison to (111)-oriented PZT films with about 3.1 × 10−2 m4/C2 of Q
33 and 40 pm/V of d
33,f
. It was also observed that two (100)-oriented films prepared by different heat treatments showed different values in piezoelectric,
dielectric, and ferroelectric properties even though only (100) orientation was characterized for both cases. This process-induced
difference may also play an important role in determining both intrinsic and extrinsic contribution to the properties, even
though these parameters seem to be more responsible for extrinsic components, such as domain wall motion. 相似文献
12.
Longhai Wang Jun Yu Yunbo Wang Junxiong Gao 《Journal of Materials Science: Materials in Electronics》2006,17(7):509-514
The PbZr0.3Ti0.7O3(PZT) thin film and multilayer PbZr0.3Ti0.7O3/PbTiO3(PZT/PT), PbTiO3/PbZr0.3Ti0.7O3/ PbTiO3(PT/PZT/PT) thin films were prepared by a Sol-Gel method on the Pt(111)/Ti/SiO2/Si(100) substrate for FeRAM application. The microstructure, ferroelectric, fatigue, dielectric, and leakage current properties
of these thin films were investigated. The results indicate that the multilayer PT/PZT/PT thin film have a better ferroelectric,
fatigue, dielectric and leakage current density properties. Its remanent polarization Pr reaches a maximum value of 21.2 μC/cm2 and the coercive field Ec gets to a minimum value of 64.2kV/cm. After 1010 cycles, it still has more than 80% remnant polarization. The PT/PZT/PT thin film exhibits lower dielectric constant and lower
dielectric loss, which is beneficial for FeRAM application. It also has the lowest leakage current density. The leakage current
mechanism of the PZT, PZT/PT and PT/PZT/PT thin films is correlated to the microstructure and can be modeled in terms of GBLC
and SCLC theory. The microstructure and electric properties of these films are correlated. The double-sided PT seed layers
enhance not only the microstructure but also the electric properties. It is evident that the PT/PZT/PT multilayer thin film
is a promising candidate for FeRAM application. 相似文献
13.
Compositionally graded ferroelectric PbZrxTi1−xO3 (PZT) films were deposited using a sputtering method and crystallized in situ at 500 °C. The films showed purely (100) or (111) crystallographic orientation when grown on Si/SiO2/TiO2/Pt substrates, while they exhibited c-axis epitaxial microstructure when prepared on MgO/Pt substrates. Their crystallographic orientation was controlled owing to a thin TiOx layer sputtered on substrates prior to PZT deposition. Analysis performed by Auger depth profile clearly confirmed the variation of composition in the films. Coercive fields from 80 kV/cm to 200 kV/cm and remnant polarization as large as 45 μC/cm2 were obtained. However, no typical offset was observed on hysteresis loops, unlike previous works related to graded PZT films. 相似文献
14.
The effects of stacking sequence and thickness toward the texture and electrical properties of heterolayered PbZr
x
Ti1−x
O3 (PZT) films, consisting of alternating PbZr0.7Ti0.3O3 and PbZr0.3Ti0.7O3 layers, have been studied. Thickness dependence is observed in the ferroelectric and dielectric behavior of the heterolayered
PZT films whereby the remanent polarization (P
r) and relative permittivity (ε) increase with thickness, while coercive field (E
c) decreases. When baked at 500 °C and thermally annealed at 650 °C, the heterolayered PZT films regardless of their stacking
sequence exhibit perovskite phase with (001)/(100) preferred orientation. Interestingly, the stacking sequence of the heterolayered
PZT films dictates the morphology of the films which eventually affects the ferroelectric and dielectric performance. The
heterolayered PZT film with PbZr0.7Ti0.3O3 as the first layer (heterolayered PZ70T30 film) exhibits a large grain size in the range of 1–3 μm and shows superior properties as compared to the heterolayered PZT
films with PbZr0.3Ti0.7O3 as the first layer (heterolayered PZ30T70 film), which exhibits a much smaller grain size. From the sub-switching field measurement according to the Rayleigh law,
there appears a lower concentration or mobility of domain walls in the small-grained heterolayered PZ30T70 films. 相似文献
15.
16.
Min Shi Gui Yang Yu Hai Lin Su Ru Zhong Zuo Yu Dong Xu Guang Wu Li Wang 《Journal of Materials Science》2011,46(13):4710-4714
CoFe2O4–Pb(Zr0.52Ti0.48)O3 (CFO–PZT) multilayered composite film was prepared on Pt/Ti/SiO2/Si substrate via a sol–gel method and spin-coating technique. Results show that PZT and CFO phases exist in the composite
film, calcined at 700 °C, besides substrate phase, and no obvious impurity phases can be detected. The composite film exhibits
layered structure with obvious boundary between CFO and PZT films. Ferroelectric and ferromagnetic properties were simultaneously
observed in the composite film, evidencing the ferroelectric and ferromagnetic properties in the composite film. The composite
film exhibits both good magnetic and electric properties, as well as, magnetoelectric (ME) effect. The saturation magnetization
value of the composite film is lower than that of the pure CFO film derived by the same processing as a result of the effect
of the nonferromagnetic PZT layers. Ferroelectric hysteresis loops reveal that saturated polarization and remanent polarization
of the composite film are lower than those of the pure PZT films. The composite film exhibits a very large ME effect, which
makes the composite film attractive for technological applications as devices. 相似文献
17.
采用溶胶-凝胶法在Pt/Ti/SiO_2/Si(111)衬底上制备了Bi_(0.975)La_(0.025)Fe_(0.975)Ni_(0.025)O_3(BLFNO)铁电薄膜。利用X射线衍射(XRD)、原子力显微镜(AFM)及其压电模式(PFM)对薄膜的晶体结构、表面形貌以及铁电畴结构进行了研究。研究发现,BLFNO为结晶良好的钙钛矿结构多晶薄膜,且薄膜表面颗粒生长均匀。PFM测试图显示铁电薄膜在自发极化下的铁电畴结构清晰,铁电电容器具有良好的铁电性能。应用铁电测试仪对Pt/BLFNO/Pt电容器进行测量,得到了饱和性良好的电滞回线。在828kV/cm的外加电场下,Pt/BLFNO/Pt电容器的剩余极化强度为74.3μC/cm~2,表明La、Ni的共掺杂没有明显抑制铁电电容器的剩余极化强度,铁电电容器具有良好的铁电性能。漏电流研究结果表明,La、Ni元素的共掺杂有效降低了薄膜的漏电流密度,在277.8kV/cm外加电场下漏电流密度在10-4 A/cm2量级,明显小于纯BFO薄膜的漏电流密度。正半支漏电流曲线满足SCLC导电机制,对于负半支曲线,当电场强度大于22.2kV/cm时,同样遵循SCLC导电机制;但是,当电场强度小于22.2kV/cm时,曲线斜率约为4.8,表明参与导电贡献的电子数较多,归因于极浅陷阱俘获的电子在外加电场作用下参与了导电行为。室温下磁滞回线测试结果表明BLFNO薄膜具有反铁磁性质。 相似文献
18.
D. E. Jain Ruth B. Sundarakannan 《Journal of Materials Science: Materials in Electronics》2016,27(4):3250-3257
Effect of weak ferroelectric perovskite, bismuth magnesium zirconate [Bi(Mg0.5Zr0.5)O3] substitution in lead-free sodium bismuth titanate [(Na0.5Bi0.5)TiO3] ceramics is studied. Influence of substitution on intrinsic and extrinsic contribution and impact on ferroelectric and piezoelectric properties are investigated. Improved spontaneous polarization (Ps), increased remnant polarization (Pr), decreased coercive field (Ec) and high piezoelectric coefficient (d33) are obtained for x = 0.01 mole fraction of Bi(Mg0.5Zr0.5)O3 substitution due to decrease in rhombohedral lattice distortion and homogeneous strain. Small rhombohedral lattice distortion (δr) and minimum homogeneous strain (δ) are the primary intrinsic parameters which favours the extrinsic parameters such as mobility of non-180° domain reorientation, domain switching and domain wall motion. Enhanced mobility softens the coercive field and increases remnant polarization to maximum. Reduced rhombohedral lattice distortion, low strain and enhanced mobility are the key factors for enhanced piezoelectric constant, highest remnant polarization and decreased coercive field in non-MPB (1 ? x)(Na0.5Bi0.5)TiO3–xBi(Mg0.5Zr0.5)O3 solid solutions. 相似文献
19.
Automated high resolution electron backscatter diffraction was used to map the local crystallographic texture of Pt and PbZr1−x
Ti
x
O3 (PZT) thin films with a resolution as high as 5 nm. The Pt and PZT films consisted of 99.9% and 94.3% {111} textured grains
(i.e., with (111) planes parallel to the substrate surface), respectively. The average Pt and PZT grain sizes were 46 ± 30 nm
and 65 ± 30 nm, respectively. Quantification of misorientation distributions and the fraction of non-{111}-textured grains
demonstrates the potential of this local texture measurement method for quantifying the ferroelectric variability limits of
PZT-based capacitors. 相似文献
20.
Feng Chen Jinrong Cheng Shenwen Yu Zhongyan Meng 《Journal of Materials Science: Materials in Electronics》2010,21(5):514-518
Pb(Zr0.53Ti0.47)O3 (PZT) thin films were prepared on La0.5Sr0.5CoO3 (LSCO) coated Si substrates by a sol–gel route. The thickness of LSCO electrode was found to modify the preferential orientation
of PZT thin films, which consequently affected the dielectric and ferroelectric properties. (100) textured PZT films with
dense columnar structure could be obtained on the top of (110) textured LSCO with thickness of 230 nm. PZT thin films prepared
on the optimized LSCO films exhibit the enhanced dielectric constant and remnant polarization of 980 and 20 μC/cm2, respectively. 相似文献