Influence of Vanadium Doping on Structural and Ferroelectric Properties of Laser Ablated SrBi2Ta2O9 Thin Films

2002 ◽  
Vol 718 ◽  
Author(s):  
Rasmi R. Das ◽  
P. Bhattacharya ◽  
W. Pérez ◽  
Ram S. Katiyar
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Ferroelectric Properties ◽  
Lattice Parameter ◽  
Partial Replacement ◽  
Processing Temperature ◽  
Ionic Radii ◽  
Vanadium Concentration ◽  
Vanadium Doping ◽  
Stretching Vibration

AbstractPulsed laser deposition technique was used to fabricate SrBi2Ta2O9 (SBT) thin films with partial replacement of penta-valent vanadium ion. In this report, we have doped certain concentrations (0, 5, 10, 15 %) of vanadium at Ta-site of SBT thin films and study their influence on the structural and electrical characteristics. Thin films were grown on platinized silicon substrates using an excimer laser (KrF, 248 nm) with an energy density of ∼ 2.5 J/cm2. Xray diffraction studies confirmed the c-axis suppression of the films at lower processing temperature and at higher annealing temperatures. The decrease in the lattice parameter with vanadium doping was attributed to the smaller ionic radii of vanadium in comparison to Ta. Raman modes of SBT thin films shifted to higher frequencies upon vanadium incorporation at Ta-site. The extra Raman mode observed around ∼860 cm-1, was attributed due to the octahedron stretching vibration in the presence of vanadium at the center of octahedral cage. SBT thin films with 5% V doping exhibit enhanced ferroelectric properties, and the ferroelectric properties were degraded for higher vanadium concentration. The SBT thin films show dielectric constant of about ∼258 with tangential loss of 0.02 at a frequency of 100 kHz. Dielectric constant decreases with increase in V-concentration and attributed to the interdiffusion of bismuth into platinum electrode. The leakage current density of the films was also increased upon vanadium incorporation in SBT thin films.

Ferroelectric Properties in Ca Substituted SrBi2Nb2O9 Thin Films

2002 ◽  
Vol 748 ◽  
Author(s):  
Rasmi R. Das ◽  
W. Pérez ◽  
P. Bhattacharya ◽  
Ram S. Katiyar
Keyword(s):  
Thin Films ◽  
Dielectric Permittivity ◽  
Ferroelectric Properties ◽  
Lattice Parameter ◽  
Partial Substitution ◽  
Homogeneous Distribution ◽  
Silicon Substrates ◽  
Ionic Radii ◽  
Structural And Electrical Properties ◽  
Polarization Axis

ABSTRACTWe have studied the influence of partial substitution of Ca (0%, 5%, 10% and 15%) on the structural and electrical properties of SrBi2Nb2O9 (SBN) thin films. Pulsed laser deposition technique was used to grow thin films on platinized silicon substrates. X-ray diffraction data confirmed the polycrystalline nature of the films with preferential orientation along the polarization axis. Incorporation of Ca at Sr-site of SBN reduced the lattice parameter and was attributed to the smaller ionic radii of Ca. The soft mode frequency at 29.5 cm-1 of SBN shifted towards higher wavenumber implied increasing the transition temperature upon Ca substitution. The grain sizes of SBN thin films vary from oval to rod like structures and improving the homogeneous distribution of grains with the increase in Ca contents. The ferroelectric properties of the films enhanced with maximum remanent polarization of 35.3 mC/cm2. The increase in the coercive field with incorporation of Ca at Sr-site was attributed to the higher electronegativity of Ca. The SBN thin films with the incoporation of Ca exhibited poor leakage current behavior. The reduction of dielectric permittivity with Ca concentration was attributed to the lower dielectric permittivity of CaBi2Nb2O9.

Fabrication of V-Substituted (Bi,M)4Ti3O12 [M = Lanthanoids] Thin Films by Chemical Solution Deposition Method

2001 ◽  
Vol 688 ◽  
Author(s):  
H. Uchida ◽  
H. Yoshikawa ◽  
I. Okada ◽  
H. Matsuda ◽  
T. Iijima ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Solution Deposition ◽  
Bismuth Titanate ◽  
Ferroelectric Properties ◽  
Ferroelectric Materials ◽  
Processing Temperature ◽  
Chemical Solution ◽  
Si Substrate ◽  
Solution Deposition ◽  
Chemical Solution Deposition Method

AbstractBismuth titanate (Bi4Ti3O12; BIT) -based ferroelectric materials are proposed from the view of the “Site-engineering”, where the Bi-site ions are substituted by lanthanoid ions (La3+ and Nd3+) and Ti-site ions by other ions with higher charge valence (V5+). In the present study, influences of vanadium (V) - substitution for (Bi,M)4Ti3O12 thin films [M = lanthanoid] on the ferroelectric properties are evaluated. V-substituted (Bi,M)4Ti3O12 films have been fabricated using a chemical solution deposition (CSD) technique on the (111)Pt/Ti/SiO2/(100)Si substrate. Remnant polarization of (Bi,La)4Ti3O12 and (Bi,Nd)4Ti3O12 films has been improved by the V-substitution independent of the coercive field. The processing temperature of BLT and BNT films could also be lowered by the V-substitution.

Effect of Cationic Substitution on Raman Spectra of SrBi2Ta2O9Ceramics and Thin Films

2003 ◽  
Vol 784 ◽  
Author(s):  
W. Perez ◽  
R. R. Das ◽  
P. S. Dobal ◽  
Y. I. Yuzyuk ◽  
P. Bhattacharya ◽  
...  
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Lattice Mismatch ◽  
Ferroelectric Properties ◽  
Low Frequency ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
Cationic Substitution ◽  
Factor Substitution ◽  
Raman Modes

ABSTRACTIn the present work micro-Raman spectroscopy has been used to understand the lattice dynamics of cation substituted SBT ceramics and thin films. Different concentrations of Ca and V were introduced into SBT lattices. Incorporation of Ca ion at Sr-site was confirmed by decrease in the lattice parameters calculated from x-ray diffraction data. The lowest Raman modes at 27 cm-1and 58 cm-1showed upward shift with increasing Ca concentration and was attributed to the lower mass and lower ionic radii of Ca. The temperature dependant Raman studies revealed the increase of the phase transition temperature with increased Ca content, and was attributed to the decrease in tolerance factor. Substitution of smaller cation at Sr site in SBT compound has increased lattice mismatch between SrO and TaO2planes inside the stable perovskite unit of SrTa2O7which has pronounced influence on ferroelectric properties of SBT. Substitution of vanadium at Ta-site of SBT did not influence the low frequency Raman modes of SBT. However, it showed a pronounced influence on the O-Ta-O stretching modes by splitting the mode frequency at 810 cm-1. The transition temperature of SBT was reduced with increasing vanadium contents.

Surface Morphologies of PVDF-TrFE/MgO Nanocomposite Thin Films and its Effect on the Ferroelectric Properties

2015 ◽  
Vol 1134 ◽  
pp. 6-11 ◽  
Author(s):  
Mohamad Hafiz Mohd Wahid ◽  
Rozana Mohd Dahan ◽  
Siti Zaleha Sa'ad ◽  
Adillah Nurashikin Arshad ◽  
Muhamad Naiman Sarip ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Magnesium Oxide ◽  
Ferroelectric Properties ◽  
Filler Loading ◽  
Nanocomposite Thin Film ◽  
Nanocomposite Thin Films ◽  
Surface Morphologies

The enhancement of ferroelectric and dielectric properties of PVDF-TrFE by incorporating various percentages of Magnesium Oxide (1 – 7%) for spin coated nanocomposite thin film was demonstrated. Observations showed uniform distribution and low agglomeration of MgO in the PVDF-TrFE nanocomposite thin film, especially for 3% MgO. Additionally, the 3% MgO incorporated into PVDF-TrFE had generated the highest Pr (88 mC/m2) and dielectric constant (13.6) in comparison other percentage compositions. However, the addition of more than 3% MgO filler loading caused a reduction in the ferroelectric and dielectric properties of the nanocomposite thin films.

Bi Effect on the Microstructure and Dielectric Properties of SrTiO3 Thin Films

2006 ◽  
Vol 514-516 ◽  
pp. 245-249 ◽  
Author(s):  
Olena Okhay ◽  
Vitor M.X. Bergano ◽  
Ai Ying Wu ◽  
Paula M. Vilarinho
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Grain Size ◽  
Low Temperatures ◽  
Room Temperature ◽  
Sol Gel ◽  
Lattice Parameter ◽  
Dielectric Anomaly ◽  
Second Phase ◽  
Si Substrates

Crystalline (Sr1-1.5xBix)TiO3 (SBiT) thin films (0.002 ≤ x ≤ 0.5) were prepared by sol-gel on Pt/TiO2/SiO2/Si substrates. Cubic monophasic SBiT films were obtained for samples with x ≤ 0.167. For films with x ≥ 0.267 a second phase identified as Bi4Ti3O12 was observed. The lattice parameter of SBiT films increases with increasing Bi content, similar to the variation observed in SBiT ceramics. No obviously variation of the grain size with the Bi content was observed. The dielectric constant ε´ at room temperature increases with increasing of Bi concentrations up to x ≤ 0.1. The loss tangent of Bi doped SrTiO3 films is approximately 0.05 and lower than undoped ST films at 10kHz. The higher values of ε´ of Bi doped ST films with x=0.1 and x=0.167 in comparison with undoped films may suppose the appearance of a dielectric anomaly at low temperatures, which will be dependent on the Bi content.

Laser-Assisted Low Temperature Processing of PZT Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
Yongfei Zhu ◽  
Jinsong Zhu ◽  
Y. J. Song ◽  
S. B. Desu
Keyword(s):  
Thin Films ◽  
Low Temperatures ◽  
Laser Annealing ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Processing Temperature ◽  
Pzt Thin Films ◽  
Step Process ◽  
Pzt Films ◽  
One Step

ABSTRACTA novel method for lowering processing temperature of ferroelectric Pb(Zr1−xTix)O3 (PZT) thin films was developed utilizing a laser-assisted two-step process. In the first step, perovskite phase was initiated in the PZT films by subjecting the films to a fornace anneal at low temperatures in the range of 470 °C to 550 °C depending on the Zr/Ti ratio. Later, the films were laser-annealed (using krF excimer laser) at room temperature to grow the perovskite phase, and to improve microstructure and ferroelectric properties. It was found that this two-step process was very effective in producing excellent quality ferroelectric PZT films at low temperatures. It should be noted that although laser annealing of amorphous and/or pyrochlore films directly (one-step process) produces perovskite phase, the ferroelectric properties of these films, irrespective of the composition, were rather unattractive. Some possible reasons for the ineffectiveness of the one-step process were discussed.

Electrical and Physical Properties of Al and Nb Doped PbTiO3 Ceramic Thin Films

2005 ◽  
Vol 475-479 ◽  
pp. 1587-1590
Author(s):  
Bo Ping Zhang ◽  
Jing Feng Li ◽  
Yan Dong ◽  
Takashi Iijima
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Constant ◽  
Ferroelectric Properties ◽  
Deposition Process ◽  
Solution Deposition ◽  
Co Doping ◽  
Ceramic Thin Films ◽  
Maximum Dielectric Constant ◽  
The Individual

A series of Pb(Ti1-xAlx)O3, Pb(Ti1-xNbx)O3 and Pb(Ti1-xAlx/2Nbx/2)O3 thin films were fabricated onto Pt/Ti/SiO2/Si(100) substrates using a chemical solution deposition process. The dielectric constant of the Pb(Ti1-xAlx)O3 thin films increased with increase of aluminum content, while a maximum dielectric constant value was observed for the Pb(Ti1-xNbx)O3 and Pb(Ti1 xAlx/2Nbx/2)O3 thin films when the doping contents were 10 and 20 mol%, respectively. The dielectric constant of the Pb(Ti0.8Al0.1Nb0.1)O3 thin film is about 600, being two times higher than those of Pb(Ti0.9Al0.1)O3 and Pb(Ti0.9Nb0.1)O3 thin films. The Pb(Ti0.8Al0.1Nb0.1)O3 thin film showed less than 10-7 A/cm2 current density at ±150 kV/cm, being superior to the leakage property of the PbTiO3, Pb(Ti0.9Al0.1)O3 and Pb(Ti0.9Nb0.1)O3 thin films. The co-doping of aluminum and niobium is more effective to increase the dielectric and ferroelectric properties as compared with the individual aluminum or niobium doping.

Growth and Layer Characterization of SrTiO3 by Atomic Layer Deposition using Sr(tBu3Cp)2 and Ti(OMe)4

2009 ◽  
Vol 1155 ◽  
Author(s):  
Mihaela Popovici ◽  
Sven Van Elshocht ◽  
Nicolas Menou ◽  
Johan Swerts ◽  
Dieter Pierreux ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Atomic Layer Deposition ◽  
Crystalline State ◽  
Atomic Layer ◽  
Lattice Parameter ◽  
Index Of Refraction ◽  
Layer Deposition ◽  
Pulse Ratio

AbstractStrontium titanate (STO) thin films (45-67 % Sr) were deposited by atomic layer deposition using Sr(tBu3Cp)2/Ti(OMe)4/H2O as precursors. The Sr content of the layers is well controlled by the precursor pulse ratio, as indicated by Rutherford backscattering spectroscopy (RBS). The amount of Sr and Ti deposited depends on the Sr:Ti pulse ratio and indicates the enhancement of the Ti precursor reactivity in the presence of Sr-OH. STO compositions that are closer to stoichiometric SrTiO3 result in denser films with correspondingly higher index of refraction. The increase (decrease) of the Sr content over (below) 50 % leads to an expansion (contraction) of the lattice parameter corresponding to cubic SrTiO3 with a perovskite structure. The dielectric constant (extracted from film thickness series) and leakage current strongly depends both on the Sr content and the crystalline state of the films.

The Effects of La Concentration on the Properties of PLT Thin Films: From the Perspective of Dram Applications

1994 ◽  
Vol 361 ◽  
Author(s):  
Seong Jun Kang ◽  
Jeong Seon Ryoo ◽  
Yung Sup Yoon
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Current Density ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Lanthanum Titanate

ABSTRACTWe have studied the effects of La concentration on the dielectric and ferroelectric properties of lead lanthanum titanate (PLT) thin films by using sol-gel method. Both the dielectric and ferroelectric properties were greatly affected by the La concentration. The dielectric constants of the films varied from 340 to 870 with varying La concentration in the range from 15 to 33 mol%. Hysteresis loop became slimmer with the increase of La concentration from 15 to 28 mol% and a little fatter again with the increase of La concentration from 28 to 33 mol%. Among the films investigated in this research, PLT(28) thin film showed the best dielectric properties for the application to the dielectrics of ULSI DRAM's. At the frequency of 100 Hz, the dielectric constant and the loss tangent of PLT(28) thin film were 940 and 0.08, respectively. Its leakage current density at 1.5×10 V/cm was 1×10−6 A/cm2. The comparison between the simulated and the experimental curves for the switching transient characteristics showed that PLT(28) thin film behaved like normal dielectrics.

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