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1.
Abstract

The influence of heat treatment and substrate materials on PLT thin films by sol-gel processing has been researched. Epitaxial growth PLT thin films with perovskite-type structure on sapphire, SrTiO3 and MgO single crystal substrates have been prepared. The epitaxial relations are (100)PLT28/(100)SrTiO3, (111)PLT28//(0001)sapphire and (100)PLT14//(100)MgO. The PLT polycrystal thin films with perovskite-type structure on Si single crystal and quartz glass substrates have been prepared. The remanent polarization Pr and the coercive field Ec of PLT15 ceramic thin films are 7.7 μc/cm2 and 34 kv/cm at 4 KHz respectively. The optical transmittance of PLT28 ceramic thin films within the wavelength range of λ = 500–1000 nm is approximately 80%.  相似文献   

2.
Epitaxial (Bi,La)4Ti3O12 (BLT) thin films, epitaxial Pb(Zr,Ti)O3 (PZT) thin films, and epitaxial multilayered BLT/PZT ferroelectric thin films with different orientations were prepared on SrTiO3 (STO) single crystal substrates by pulsed laser deposition. From X-ray pole-figures and electron diffraction patterns, the epitaxial orientation relationships between BLT layers, PZT layers, and STO substrates were identified to be (1) BLT(001)//PZT(001)//STO(001), and BLT[110]//PZT[100]//STO[100] for the multilayered thin films on (001)-oriented STO substrates, and (2) BLT(118)//PZT(011)//STO(011), and $ {\text{BLT}}{\left[ {\overline{1} \overline{1} 0} \right]}//{\text{PZT}}{\left[ {100} \right]}//{\text{SrTiO}}_{3} {\left[ {100} \right]} $ for the multilayered films on (011)-oriented STO substrates. Tri-layered films of the same compositions showed well-defined hysteresis loops as well as a high fatigue resistance up to 1?×?1010 switching cycles.  相似文献   

3.
Abstract

Pulsed laser ablation has been used to deposit ferroelectric Pb(Zr, Ti)O3 (PZT) thin films on Si(100) and on yttrium-treated Si(100) substrates. The yttrium (Y) treatment of a Si surface followed by oxidation resulted in formation of a very thin, Y-enhanced SiO2 antidiffusion barrier layer, thereby suppressing the undesirable PZT/Si interdiffusion. The best PZT film grown on Y-treated Si(100) had a breakdown voltage of 0.6 MV/cm, a coercive field of 71 KV/cm, and a remanent polarization of 18 μC/cm2.  相似文献   

4.
Bilayered thin films consisting of Pb(Zr0.52Ti0.48) O3 (PZT) and (Bi3.15Nd0.85)Ti3O12 (BNT) layers are successfully deposited on Si(100)/SiO2/Ti/Pt substrate by a combined process involving sol-gel and RF-sputtering. Their dielectric properties cannot be described by the simple rule of mixture on the basis of the series connection model. There occurs a dielectric layer of lower dielectric permittivity in the bilayered thin film, which degrades the polarization behaviors. The bilayered film gives rise to an improvement in fatigue resistance up to 1010 switching cycles. Moreover, the domain pinning effect after polarization switching is reduced greatly as compared to that of single layered PZT and BNT thin films.  相似文献   

5.
Pure BiFeO3 (BFO) and rare earth (RE) ion co-doped (Bi0.9RE0.1)(Fe0.975Mn0.025)O3 (RE?=?Sm, Tb and Ho, denoted by BSFM, BTFM and BHFM) thin films were prepared on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. Formations of distorted rhombohedral perovskite structure for the thin films were confirmed by using an X-ray diffraction and a Raman scattering analysis. Microstructural features for the thin films were examined by using a scanning electron microscopic analysis. Among the thin films, the lowest leakage current density of 1.22?×?10?6 A/cm2 (at 100 kV/cm), large remnant polarization (2Pr) of 72.4 μC/cm2 and low coercive field (2E c ) of 689 kV/cm (at 980 kV/cm) were measured for the BTFM thin film.  相似文献   

6.
The BiFeO3 (BFO) and the gadolinium and transition metal ions co-doped (Bi0.9Gd0.1)(Fe0.975 TM 0.025)O3-δ (TM?=?Ni, Co and Cr, BGFNi, BGFCo and BGFCr) thin films were prepared on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. Compared to the pure BFO, improved electrical and ferroelectric properties were observed in the co-doped (Bi0.9Gd0.1)(Fe0.975 TM 0.025)O3-δ thin films. Among the thin films, the BGFCr thin film exhibited large remnant polarization (2P r ), low coercive field (2E c ), and reduced leakage current density, which are 136 μC/cm2, 1360 kV/cm at 1470 kV/cm, and 5.14?×?10-6 A/cm2 at 100 kV/cm, respectively.  相似文献   

7.
LaNiO3 (LNO) thin films were prepared on Si (100) wafer by MOD method. Pb(Zr, Ti)O3 ferroelectric thin films and their compositionally graded thin films were prepared on LNO/Si (100) substrates by a modified sol–gel method. The composition depth profile of a graded film was determined by using a combination of Auger electron spectroscopy and Ar ion etching. The results confirmed that the processing method produces graded composition change. XRD analysis showed that the graded thin film possessed a composite structure of tetragonal and rhombohedral. The dielectric constant of the graded thin films was higher than that of each thin film unit, but the loss tangent was near to each other at 10 kHz. The temperature characteristics of the dielectric constant of the graded thin films at different frequencies showed three peaks and ferroelectric relaxor feature to some extent. Hysteresis loops showed that graded thin film had higher remanent polarization, smaller coercive field than each thin film unit. The pyroelectric coefficient of the graded thin films increased gradually with temperature, and was higher than that of each thin film unit.  相似文献   

8.
By the radio frequency (RF) magnetron sputtering methods, (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 (BSTZ) ferroelectric thin films were deposited on the Pt/Ti/SiO2/Si(100) substrates. The crystal structural and microstructure of these thin films were analyzed by means of the XRD, SEM, and AFM. Moreover, the dielectric characteristics were also investigated by the C-V and J-E analyses. The optimal deposition parameters for these BSTZ thin films were: RF power is 160 W, oxygen concentration is 25%, substrate temperature is 580°C, and chamber pressure is 0.075 mPa. Under these optimal deposition conditions, the (111) and (110) oriented polycrystalline of the BSTZ thin films grow easily. And under a bias voltage of 0.5 MV/cm, the dielectric constant and leakage current density of the BSTZ thin films are 191 and 3×10?8 A/cm2, respectively. In addition, under various measured temperatures (0 ~ 80°C) and frequencies (100 kHz ~ 1 MHz), all the dielectric constants remain almost unchanged. Compared to BSTZ thin films reported previously, in this study, the deposited thin films have the advantage of lower leakage current and hence are suitable for the applications of dynamic random access memory.  相似文献   

9.
Transition metal (Ni, Mn, Cu) doped Bi0.9Nd0.1FeO3 thin films were prepared on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. Compared to pure BiFeO3 (BFO) thin film, improved ferroelectric and leakage current properties were observed in the transition metal doped thin films. The values of remnant polarization (2P r ) and coercive electric field (2E c ) of the transition metal doped thin films were 59 μC/cm2 and 690 kV/cm at 700 kV/cm for the Ni-doped Bi0.9Nd0.1FeO3 thin film, 57 μC/cm2 and 523 kV/cm at 670 kV/cm for the Mn-doped thin film, and 85 μC/cm2 and 729 kV/cm at 700 kV/cm for the Cu-doped thin film, respectively. The 2P r values observed in the transition metal doped thin films were much larger than that of the BFO thin film, 21 μC/cm2 at 660 kV/cm. Also the 2E c values of in the transition metal doped thin films were lower than that of the BFO thin film, 749 kV/cm at 660 kV/cm. The reduced leakage current density was observed in the transition metal doped thin films, which is approximately two orders of magnitude lower than the BFO thin film, 2.6?×?10?3 A/cm2 at 100 kV/cm.  相似文献   

10.
(Bi,La)4Ti3O12 (BLT) thin films were prepared on Pt-coated Si (Pt/Ti/SiO2/Si(100)) substrates by chemical solution deposition method. The effect of heating process on structural and electrical properties of BLT thin films was investigated. The c-axis preferentially oriented films were obtained by lower drying temperature with heating from bottom by a hot plate or IR lamp heater. On the other hand, randomly oriented films were obtained by higher drying temperature with heating from top of films by IR lamp heater or with heating substrate all around by tube type furnace. The orientation of BLT thin films deposited on Pt-coated substrates can be controlled by heating process.  相似文献   

11.
Thin films made of (100)/(001)-oriented Pb(Zr, Ti)O3 (PZT) were deposited by liquid-delivery metal-organic chemical vapor deposition on Ir/MgAl2O4/SiO2/Si(100) substrates. For comparison, PZT thin films were also deposited on Ir/MgO(100) substrates. The X-ray scan spectra for the (202) reflections revealed that the PZT films have four-fold symmetry. It indicates that the PZT films were epitaxially grown as a cube-on-cube structure on both substrates. The switchable polarization (Qsw) of the PZT capacitors on the silicon substrate was only 23 C/cm2 at 1.8 V; however, Qsw of PZT capacitors on MgO was 99 C/cm2. In the case of PZT films deposited on silicon, the volume fraction of (001)-oriented domains (which contribute to polarization switching) was 15.1% (calculated from an XRD pattern). This result is due to the lower Qsw of PZT capacitors on silicon. By piezoresponse-force microscopy, switchable and unswitchable domains could be identified by imaging color contrast, namely, (001) and (100) domains, respectively. Consequently, domain distribution of the PZT film on a silicon substrate indicates that the (001) domain exists in the (100) domain matrix.  相似文献   

12.
Abstract

We have grown stoichiometric pure perovskite phase Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) thin films and PMN-PT/SrRuO3 heterostructures on miscut (100) SrTiO3 substrates by pulsed laser deposition. X-ray diffraction θ–2θ scans show that the PMN-PT films are purely c-axis oriented. The off-axis Φ scans show that the heterostructures grow “cube-on-cube” with an in-plane epitaxial arrangement of PMN-PT[100], [010] // SrRuO3[001] // SrTiO3[100] and PMN-PT[010], [100] // SrRuO3[110] // SrTiO3[010]. The crystalline quality of the films found to be comparable to that of bulk single crystals. The AFM images show that the SrRuO3 and PMN-PT layers have smooth surfaces with root mean square roughness of 9Å. These epitaxial heterostructures can be used for the fabrication of piezoelectric devices.  相似文献   

13.
Ba(ZrxTi1-x)O3 (BZT) thin films with different Zr contents were deposited on (100)MgO and (100)Pt/(100)MgO substrates by RF-magnetron sputtering using metal targets. The BZT thin films had a single perovskite phase with only (001)/(100) orientation. In all cases, the ratio of Ba/Ti was stoichiometry and BZT films possess a dense microstructure. The grain size was decreased and BZT thin films showed ferroelectric-to-paraelectric properties with increasing Zr content. At room temperature, the tunability of nearly 30% was achieved at 1 MHz; meanwhile, a relatively low dielectric loss was obtained. These results indicated that we succeeded in depositing high-quality and potential tunable ferroelectrics.  相似文献   

14.
Abstract

Ferroelectric Pb(Zr,Ti)O3 (PZT) thin films were prepared by pulsed excimer laser deposition on Silicon-on-Insulator (SOI) substrates with and without an electrode. Their properties can be improved by rapid thermal annealing, based on the structural and interfacial characteristics analysis by X-ray diffraction, Rutherford backscattering spectroscopy and automatic spreading resistance measurements. The thin films were revealed of to be polycrystalline perovskite structure with mainly ?100? and ?110? orientations; the crystallite size and the structure are dependent on the annealing time. The PZT thin films did not interact with the top silicon layers of SOI, and the composition was on the tetragonal side of the morphotropic phase boundary in the PbTiO3-PbZrO3 phase diagram.  相似文献   

15.
Abstract

Comparison has been made between the microstructures and electrical properties of Pb0·95La0·05TiO3 (PLT) thin films deposited on bare (100)MgO and on Pt/(100)MgO. Nearly perfect epitaxial PLT was grown on (100)MgO. (100)-oriented Pt film was obtained via coalescence of Pt islands formed on MgO. Highly c-axis oriented PLT thin film was successfully grown on the Pt bottom electrode with an electrically conductive network structure. High detectivity of 3·5 × 108 and 2·6 × 108 cm√Hz/W was obtained at 30 Hz without any poling treatments from the PLT/MgO- and PLT/Pt/MgO-based infrared detectors, respectively.  相似文献   

16.
The phase formation and electrical properties of (Bi, La)4Ti3O12 (BLT) thin film and V-, Sm-doped BLT thin films prepared by the chemical solution deposition method on Pt/TiO2/SiO2/Si substrates have been investigated. It was observed that the microstructure and electrical properties of BLT thin films dramatically varied with V- and Sm-doping. The crystallinity and grain size of BLT thin films were definitely increased by V- and Sm-doping into BLT films, which resulted in the enhancement of remanent polarization in doped BLT films. The remanent polarization (Pr) of Sm-doped BLT films annealed for 3 min by an RTA system was about 9 C/cm2. The V- and Sm-doped BLT films also exhibited good fatigue characteristics under bipolar stressing to 1010 cycles.  相似文献   

17.
《Integrated ferroelectrics》2013,141(1):1257-1264
PZT thin films are deposited on SiO2/Si substrate by metallo-organic decomposition (MOD) process, using SrTiO3 (STO) as buffer layer for textured growth. The STO layers deposited on SiO2/Si substrate by pulsed laser deposition process show (100)/(200) preferred orientation, whereas the STO buffer layer deposited on silica substrate using spin-coating technique show random orientation behavior. The use of STO as buffer layers enhanced the crystallization and the preferred orientations of the PZT films. The PZT on STO buffered SiO2/Si substrates thus obtained possess high refractive index, (n)PZT/STO = 2.1159, and are of good enough quality for optical waveguide applications.  相似文献   

18.
Abstract

Barium titanate (BaTiO3) thin films with high (211) orientation have been prepared on Pt(111)/Si(100) substrates by R. F. magnetron sputtering at a substrate temperature between 550°C and 580°C in an Ar/O2 atmosphere. The I-V curve of a thin film capacitor (Ag-BaTiO3-Pt) has been measured and the C-V curves are obtained for frequencies between 100Hz and 1MHz. Neither the I-V curve nor the C-V curves are symmetrical and a very large change in the slope of all curves is found to occur at ~+0.5v.  相似文献   

19.
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 600C. The synthesized BNTS films revealed a random orientation having a strong 117 reflection. The BNTS thin films prepared between 600C and 700C 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   

20.
Lead- and bismuth-free Ba(Ti1 ? x Zr x )O3 (BTZ) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by the chemical solution deposition (CSD) process. The single phase BTZ thin films were obtained at 650°C by conventional process and the control of lattice parameter a was possible by Zr substitution. As the D-E hysteresis loops and J-V characteristics depended on the precipitates on film surface, the fabrication process was reexamined by 2-step sintering process. Consequently the decreasing of first sintering time was able to prevent the precipitates, and the larger grain of about 40–50 nm were obtained by additional sintering for 2 hour.  相似文献   

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