Dielectric Properties of Ba1−xSxTiO3 Films Grown on LaAlO3 Substrates

1999 ◽  
Vol 603 ◽  
Author(s):  
Y. Gim ◽  
T. Hudson ◽  
Y. Fan ◽  
A. T. Findikoglu ◽  
C. Kwon ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Barium Strontium Titanate ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Temperature Dependent ◽  
Peak Voltage ◽  
Capacitance Measurements ◽  
Barium Strontium ◽  
Bst Films

AbstractWe report the crystal structures and dielectric properties of barium strontium titanate, Ba1−xSrxTiO3 (BST), films deposited on LaAlO3 substrates using pulsed laser deposition, where x = 0.1 to 0.9 at an interval of 0.1. We have found that when x < 0.4 the c-axis is parallel to the plane of the substrate but normal as x approaches 1. Temperature-dependent capacitance measurements at 1 MHz show that the capacitance has a peak and that the peak temperature decreases with increasing x. We have found that the peak temperatures of the films are about 70 °C higher than those of bulk BSTs when x < 0.4. From room-temperature capacitance (C) vs applied voltage (V) measurements, we have found that the C-V curves of the BST films exhibit hysteresis except for x = 0.9 and that the peak voltage at which the capacitance becomes maximum decreases with increasing x. At room temperature, the Ba0.6Sr0.4 TiO3 film exhibits the largest capacitance tunability (≈ 37%) with an applied electric field of 40 kV/cm.

DIELECTRIC PROPERTIES OF EPITAXIAL Ba1-xSrxTiO3 FILMS ON MgO SUBSTRATES

2011 ◽  
Vol 04 (01) ◽  
pp. 41-44 ◽  
Author(s):  
BAE HO PARK ◽  
Y. R. LI ◽  
J. XIONG ◽  
Q. X. JIA
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Strontium Titanate ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Strong Function ◽  
Barium Strontium ◽  
Field Dependent

We have systematically studied the dielectric properties of epitaxial barium strontium titanate, Ba1-xSrxTiO3 (x = 0.0, 0.1, 0.2, …, 1.0), films on MgO substrates grown by pulsed laser deposition. The dielectric properties of Ba1-xSrxTiO3 films at a frequency of 1 MHz and room temperature are a strong function of Ba/Sr ratio. The degree of electric field dependent dielectric constant is more pronounced with decrease of x values. The largest dielectric tunability and the figure of merit (or tunability/loss) are obtained at x = 0.3 and at x = 0.4, respectively.

Effects of thermal misfit strains on dielectric features of sandwich barium strontium titanate multilayer thin films on metal plates

2021 ◽  
pp. 2150030
Author(s):  
Hanting Dong ◽  
Liang Ke ◽  
Xiangjun Hui ◽  
Jiangfeng Mao ◽  
Haiqing Du ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Composition Range ◽  
Multilayer Films ◽  
Multilayer Thin Films ◽  
Barium Strontium ◽  
Metal Plates ◽  
Bst Films

Effects of thermal misfit strains on dielectric features for sandwich structural barium strontium titanate (BST) thin films on metal plates were investigated via a modified thermodynamic model. When TEC of substrates is closer to that of BST, larger permittivity and tunability can be received. The tendency of permittivities and tunabilities of such films as a function of TEC of substrates agrees with that of single compositional BST films and compositionally graded BST multilayer films. The highest tunability reaches 60% at the biasing field of 300 kV/cm when the films are onto Ti metal. Moreover, Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3 structure can obtain higher tunability than Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3 structure, while Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3 films show better compatible composition range for relatively larger tunability. Dielectric properties of sandwich-like BST films in some references can also be analyzed based on our calculated results.

Pulsed Laser Deposition of BaxSr1−xTiO3 Films on MgO, LaAlO3 and SrTiO3 for Tunable Microwave Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
Wontae Chang ◽  
James S. Horwitz ◽  
Won-Jeong Kim ◽  
Jeffrey M. Pond ◽  
Steven W. Kirchoefer ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electric Field ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Dielectric Constants ◽  
Laser Deposition ◽  
Film Stress ◽  
Donor Acceptor ◽  
Bst Films

AbstractSingle phase BaxSr1−xTiO3 (BST) films (∼0.5-7 μm thick) have been deposited onto single crystal substrates (MgO, LaAlO3, SrTiO3) by pulsed laser deposition. Silver interdigitated electrodes were deposited on top of the ferroelectric film. The room temperature capacitance and dielectric Q (1/tanδ) of the film have been measured as a function of electric field (≤80 kV/cm) at 1 - 20 GHz. The dielectric properties of the film are observed to strongly depend on substrate type and post-deposition processing. After annealing (≤1000° C), it was observed that the dielectric constant and % tuning decreased and the dielectric Q increased for films deposited onto MgO, and the opposite effect was observed for films deposited onto LaA1O3. Presumably, this change in dielectric properties is due to the changes in film stress. Very thin (∼50 Å) amorphous BST films were successfully used as a stress-relief layer for the subsequently deposited crystalline BST (∼5000 Å) films to maximize % tuning and dielectric Q. Films have been deposited from stoichiometric targets and targets that have excess Ba and Sr. The additional Ba and Sr has been added to the target to compensate for deficiencies in Ba and Sr observed in the deposited BST (x=0.5) films. Films deposited from compensated targets have higher dielectric constants than films deposited from stoichiometric targets. Donor/acceptor dopants have also been added to the BST target (Mn, W, Fe ≤4 mol.%) to further improve the dielectric properties. The relationship between the dielectric constant, the dielectric Q, the change in dielectric constant with electric field is discussed.

Low Temperature Growth Of Barium Strontium Titanate Films By Ultraviolet-Assisted Pulsed Laser Deposition

2000 ◽  
Vol 617 ◽  
Author(s):  
V. Craciun ◽  
J. M. Howard ◽  
E. S. Lambers ◽  
R. K. Singh
Keyword(s):  
Pulsed Laser Deposition ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Photoelectron Spectroscopy ◽  
Perovskite Phase ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Flat Band ◽  
Si Substrates ◽  
Barium Strontium

AbstractBarium strontium titanate (BST) thin films were grown directly on Si substrates by an in situ ultraviolet (UV)-assisted pulsed laser deposition (UVPLD) technique. With respect to films grown by conventional (i.e. without UV illumination) pulsed laser deposition (PLD), the UVPLD grown films exhibited improved structural and electrical properties. The dielectric constant of a 40-nm thick film deposited at 650 °C was determined to be 281, the leakage current density was approximately 4×10−8 A/cm2at 100 kV/cm, and the density of interface states at the flat-band voltage was found to be approximately 5.6×1011 eV−1 cm−2 X-ray photoelectron spectroscopy investigations found that the surface of the grown films exhibited an additional Ba-containing phase, besides the usual BST perovskite phase, which was likely caused by stress and/or oxygen vacancies. The amount of this new phase was always smaller and very superficial for UVPLD grown films, which can explain their better overall properties.

Effect of Laser Energy and Laser Pulses on the Microstructure, Composition and Properties of Barium Strontium Titanate Thin Films Synthesized by Pulsed Laser Deposition

2000 ◽  
Vol 656 ◽  
Author(s):  
Costas G. Fountzoulas ◽  
J. D. Demaree ◽  
Steven H. Mcknight
Keyword(s):  
Thin Films ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Pulsed Laser Deposition ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Zone Model ◽  
Barium Strontium

ABSTRACTBarium strontium titanate (BSTO) films were synthesized by the pulsed laser deposition technique (PLD) on silicon substrates at room temperature. The thin films were synthesized at ambient temperature and 30 mT oxygen partial pressure, with 300, 400 and 500 mJ/cm2 laser fluence at 5, 10 and 20 pulses per second on silicon wafer substrates. All films were subsequently post-annealed at 750°C in a continuous oxygen stream. The microstructure, crystallinity and lattice constant of the BSTO films were studied with the aid of atomic force microscopy (FEM) and Glancing Angle X-ray Diffraction analysis (GAXRD). The hardness and modulus of elasticity of the films were studied with the aid of a nanohardness indenter. The film stoichiometry was determined with the aid of Rutherford Backscattering Spectrometry (RBS). The results of this research will be combined with the results of our previous work [1, 2] on the effect of substrate temperature and oxygen partial pressure on the microstructure and properties of the BSTO films in order to construct a structural zone model (SZM) of the BSTO films synthesized by PLD.

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