Properties Variation with Composition of Single-Crystal Pb(ZrxTi1−x,)O3 Thin Films Prepared by MOCVD

1995 ◽  
Vol 401 ◽  
Author(s):  
C. M. Foster ◽  
G.-R. Bai ◽  
Z. Li ◽  
R. Jammy ◽  
L. A. Wills ◽  
...  

AbstractSingle-crystal thin films covering the full compositional range of Pb(ZrxTi1−x)O3(PZT) 0≤x≤1 have been deposited by metal-organic chemical vapor deposition (MOCVD). The films were grown on epitaxial, RF-sputter-deposited SrRuO3 thin film electrodes on (001) SrTiO3 substrates. X-ray diffraction (XRD), energy-dispersive electron spectroscopy (EDS) and optical waveguiding were used to characterize the crystalline structure, composition, refractive index, and film thickness of the deposited films. We found that the PZT films were single-crystalline for all compositions exhibiting cube-on-cube epitaxy with the substrate with very high degrees of crystallinity and orientation. We report the systematic variations in the optical, dielectric, polarization, and transport properties as a function of composition and the epitaxy-induced modifications in the solid-solution phase diagram of this system. These films exhibited electronic properties which showed clear systematic variations with composition. High values of remnant polarization (30–55 μC/cm2) were observed at all ferroelectric compositions. Unlike previous studies, the dielectric constant exhibited a clear dependence on composition with values ranging from 225–650. The coercive fields decreased with increasing Zr concentration to a minimum of 20 kV/cm at the (70/30) composition. In addition, these films exhibited both high resistivity and dielectric-breakdown strength (˜1013 Ω-cm at 100 kV/cm and >300 kV/cm, respectively) without any compensative doping.

2003 ◽  
Vol 10 (04) ◽  
pp. 591-604 ◽  
Author(s):  
Hyeong Joon Kim ◽  
Ju Cheol Shin ◽  
Cheol Seong Hwang ◽  
Sang Yong No

(Pb,La)TiO 3 (PLT) and Pb(Zr,Ti)O 3 (PZT) thin films were deposited on Pt/SiO2/Si substrate by metal-organic chemical vapor deposition (MOCVD) using a solid delivery system. The domain configurations of the deposited PLT thin films were investigated, and the film with a columnar structure exhibited a very stable write/read operation for the domain memory application. Electrical properties of PLT, PZT and rf-sputter-deposited (Ba,Sr)TiO 3 (BST) thin films were measured, and their conduction mechanisms were analyzed. The composition and thickness uniformity of BST thin films deposited by the low temperature MOCVD method on a patterned wafer with 0.15 μm-diameter contact holes were investigated, and complete thickness and composition uniformity were obtained especially for the case of a dome-wall-type chamber with a wall temperature of 450°C.


1994 ◽  
Vol 9 (5) ◽  
pp. 1104-1111 ◽  
Author(s):  
Nobuhiko Kubota ◽  
Yuh Shiohara ◽  
Shoji Tanaka

We prepared the superconducting Bi-Sr-Ca-Cu-O thin films on Y3Al5O12 (YAG) single crystal substrates by metal-organic chemical vapor deposition (MOCVD). This film of 50 nm thickness on a YAG substrate showed c-axis orientation clearly, and the zero-resistivity (Tc-zero) was achieved at 66 K. The film has the advantageous property of surface smoothness compared with the film fabricated on MgO and SrTiO3 single-crystal substrates. The surface property of the YAG substrate seems to influence the film quality.


Author(s):  
Jason R. Heffelfinger ◽  
C. Barry Carter

Yttria-stabilized zirconia (YSZ) is currently used in a variety of applications including oxygen sensors, fuel cells, coatings for semiconductor lasers, and buffer layers for high-temperature superconducting films. Thin films of YSZ have been grown by metal-organic chemical vapor deposition, electrochemical vapor deposition, pulse-laser deposition (PLD), electron-beam evaporation, and sputtering. In this investigation, PLD was used to grow thin films of YSZ on (100) MgO substrates. This system proves to be an interesting example of relationships between interfaces and extrinsic dislocations in thin films of YSZ.In this experiment, a freshly cleaved (100) MgO substrate surface was prepared for deposition by cleaving a lmm-thick slice from a single-crystal MgO cube. The YSZ target material which contained 10mol% yttria was prepared from powders and sintered to 85% of theoretical density. The laser system used for the depositions was a Lambda Physik 210i excimer laser operating with KrF (λ=248nm, 1Hz repetition rate, average energy per pulse of 100mJ).


Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 697
Author(s):  
Yu-He Liu ◽  
Xiao-Yan Liu ◽  
Hui Sun ◽  
Bo Dai ◽  
Peng Zhang ◽  
...  

Here, the electrical properties of NiO thin films grown on glass and Al2O3 (0001) substrates have been investigated. It was found that the resistivity of NiO thin films strongly depends on oxygen stoichiometry. Nearly perfect stoichiometry yields extremely high resistivity. In contrast, off-stoichiometric thin films possess much lower resistivity, especially for oxygen-rich composition. A side-by-side comparison of energy loss near the edge structure spectra of Ni L3 edges between our NiO thin films and other theoretical spectra rules out the existence of Ni3+ in NiO thin films, which contradicts the traditional hypothesis. In addition, epitaxial NiO thin films grown on Al2O3 (0001) single crystal substrates exhibit much higher resistivity than those on glass substrates, even if they are deposited simultaneously. This feature indicates the microstructure dependence of electrical properties.


1995 ◽  
Vol 388 ◽  
Author(s):  
Rand R. Biggers. ◽  
M. Grant Norton ◽  
I. Maartense ◽  
T.L. Peterson ◽  
E. K. Moser ◽  
...  

AbstractThe pulsed-laser deposition (PLD) technique utilizes one of the most energetic beams available to form thin films of the superconducting oxide YBa2Cu3O7 (YBCO). IN this study we examine the growth of YBCO at very high laser fluences (25 to 40 J/cm2); a more typical fluence for PLD would be nearer to 3 J/cm2. the use of high fluences leads to unique film microstructures which, in some cases, appear to be related to the correspondingly higher moveabilities of the adatoms. Films grown on vicinal substrates, using high laser fluences, exhibited well-defined elongated granular morphologies (with excellent transition temperature, Tc, and critical current density, Jc). Films grown on vicinal substrates using off-axis magnetron sputtering, plasma-enhanced metal organic chemical vapor deposition (PE-MOCVD), or PLD at more typical laser fluences showed some similar morphologies, but less well-defined. Under certain growth conditions, using high laser fluences with (001) oriented substrates, the YBCO films can exhibit a mixture of a- and c-axis growth where both crystallographic orientations nucleate on the substrate surface at the same time, and grow in concert. the ratio of a-axis oriented to c-axis oriented grains is strongly affected by the pulse repetition rate of the laser.


Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 333
Author(s):  
Pedro Llovera-Segovia ◽  
Gustavo Ortega-Braña ◽  
Vicente Fuster-Roig ◽  
Alfredo Quijano-López

Piezoelectric polymer cellular films have been developed and improved in the past decades. These piezoelectric materials are based on the polarization of the internal cells by means of induced discharges in the gas inside the cells. Internal discharges are driven by an external applied electric field. With this polarization method, cellular polypropylene (PP) polymers exhibit a high piezoelectric coefficient d33 and have been investigated because of their low dielectric polarization, high resistivity, and flexibility. Charging polymers foams is normally obtained by applying a corona discharge to the surface with a single tip electrode-plane arrangement or a triode electrode, which consists of a tip electrode-plane structure with a controlled potential intermediate mesh. Corona charging allows the surface potential of the sample to rise without breakdown or surface flashover. A charging method has been developed without corona discharge, and this has provided good results. In our work, a method has been developed to polarize polypropylene foams by applying an insulated high-voltage electrode on the surface of the sample. The dielectric layer in series with the sample allows for a high internal electric field to be reached in the sample but avoids dielectric breakdown of the sample. The distribution of the electric field between the sample and the dielectric barrier has been calculated. Experimental results with three different electrodes present good outcome in agreement with the calculations. High d33 constants of about 880 pC/N have been obtained. Mapping of the d33 constant on the surface has also been carried out showing good homogeneity on the area under the electrode.


2004 ◽  
Vol 449-452 ◽  
pp. 997-1000 ◽  
Author(s):  
Gwang Pyo Choi ◽  
Yong Joo Park ◽  
Whyo Sup Noh ◽  
Jin Seong Park

Tin oxide thin films were deposited at 375 °C on α-alumina substrate by metal-organic chemical vapor deposition (MOCVD) process. A number of hillocks on the film were formed after air annealing at 500 °C for 30 min and few things in N2 annealing. The oxygen content and the binding energy after air annealing came to close the stoichiometric SnO2. The cauliflower hillocks of the film seem to be formed by the continuous migration of crystallites from a cauliflower grain on the substrate to release the stress due to the increase of oxygen content and volume.


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