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Title: Switchable and tunable film bulk acoustic resonator fabricated using barium strontium titanate active layer and Ta{sub 2}O{sub 5}/SiO{sub 2} acoustic reflector

Abstract

A solidly mounted acoustic resonator was fabricated using a Ba{sub 0.60}Sr{sub 0.40}TiO{sub 3} (BST) film deposited by metal organic chemical vapor deposition. The device was acoustically isolated from the substrate using a Bragg reflector consisting of three pairs of Ta{sub 2}O{sub 5}/SiO{sub 2} layers deposited by chemical solution deposition. Transmission electron microscopy verified that the Bragg reflector was not affected by the high temperatures and oxidizing conditions necessary to process high quality BST films. Electrical characterization of the resonator demonstrated a quality factor (Q) of 320 and an electromechanical coupling coefficient (K{sub t}{sup 2}) of 7.0% at 11 V.

Authors:
;  [1]; ;  [2]; ; ; ;  [3]
  1. Structured Materials Industries, Inc., Piscataway, New Jersey 08854 (United States)
  2. Department of Electrical and Computer Engineering, Colorado State University at Colorado Springs, Colorado Springs, Colorado 80933 (United States)
  3. Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States)
Publication Date:
OSTI Identifier:
22594396
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACOUSTICS; BARIUM COMPOUNDS; CHEMICAL VAPOR DEPOSITION; DEPOSITS; FILMS; LAYERS; ORGANOMETALLIC COMPOUNDS; QUALITY FACTOR; RESONATORS; SILICA; SILICON OXIDES; STRONTIUM; STRONTIUM TITANATES; SUBSTRATES; TANTALUM OXIDES; TEMPERATURE RANGE 0400-1000 K; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Sbrockey, N. M., E-mail: sbrockey@structuredmaterials.com, Tompa, G. S., Kalkur, T. S., Mansour, A., Khassaf, H., Yu, H., Aindow, M., and Alpay, S. P. Switchable and tunable film bulk acoustic resonator fabricated using barium strontium titanate active layer and Ta{sub 2}O{sub 5}/SiO{sub 2} acoustic reflector. United States: N. p., 2016. Web. doi:10.1063/1.4960361.
Sbrockey, N. M., E-mail: sbrockey@structuredmaterials.com, Tompa, G. S., Kalkur, T. S., Mansour, A., Khassaf, H., Yu, H., Aindow, M., & Alpay, S. P. Switchable and tunable film bulk acoustic resonator fabricated using barium strontium titanate active layer and Ta{sub 2}O{sub 5}/SiO{sub 2} acoustic reflector. United States. doi:10.1063/1.4960361.
Sbrockey, N. M., E-mail: sbrockey@structuredmaterials.com, Tompa, G. S., Kalkur, T. S., Mansour, A., Khassaf, H., Yu, H., Aindow, M., and Alpay, S. P. 2016. "Switchable and tunable film bulk acoustic resonator fabricated using barium strontium titanate active layer and Ta{sub 2}O{sub 5}/SiO{sub 2} acoustic reflector". United States. doi:10.1063/1.4960361.
@article{osti_22594396,
title = {Switchable and tunable film bulk acoustic resonator fabricated using barium strontium titanate active layer and Ta{sub 2}O{sub 5}/SiO{sub 2} acoustic reflector},
author = {Sbrockey, N. M., E-mail: sbrockey@structuredmaterials.com and Tompa, G. S. and Kalkur, T. S. and Mansour, A. and Khassaf, H. and Yu, H. and Aindow, M. and Alpay, S. P.},
abstractNote = {A solidly mounted acoustic resonator was fabricated using a Ba{sub 0.60}Sr{sub 0.40}TiO{sub 3} (BST) film deposited by metal organic chemical vapor deposition. The device was acoustically isolated from the substrate using a Bragg reflector consisting of three pairs of Ta{sub 2}O{sub 5}/SiO{sub 2} layers deposited by chemical solution deposition. Transmission electron microscopy verified that the Bragg reflector was not affected by the high temperatures and oxidizing conditions necessary to process high quality BST films. Electrical characterization of the resonator demonstrated a quality factor (Q) of 320 and an electromechanical coupling coefficient (K{sub t}{sup 2}) of 7.0% at 11 V.},
doi = {10.1063/1.4960361},
journal = {Applied Physics Letters},
number = 5,
volume = 109,
place = {United States},
year = 2016,
month = 8
}
  • A tunable metamaterial with resonance frequency at terahertz (THz) was developed. Electromagnetic response of the metamaterial was characterized with THz time domain spectrometer at various direct current electric fields. The resonance frequency increased monotonously with increasing electric field. The finite difference time domain method was used to simulate the transmission spectra of the metamaterial at THz frequencies. By comparing the simulated resonance frequency with the experimental curve, dielectric property of the Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} (BST60) thin film at THz, over 0–33 kV/cm, was evaluated.
  • Piezoelectric properties of epitaxial (001) barium strontium titanate (BST) films are computed as functions of composition, misfit strain, and temperature using a non-linear thermodynamic model. Results show that through adjusting in-plane strains, a highly adaptive rhombohedral ferroelectric phase can be stabilized at room temperature with outstanding piezoelectric response exceeding those of lead based piezoceramics. Furthermore, by adjusting the composition and the in-plane misfit, an electrically tunable piezoelectric response can be obtained in the paraelectric state. These findings indicate that strain engineered BST films can be utilized in the development of electrically tunable and switchable surface and bulk acoustic wave resonators.
  • Loss reduction is critical to develop Ba{sub 1−x}Sr{sub x}TiO{sub 3} thin film tunable microwave dielectric components and dielectric energy storage devices. The presence of ferroelectricity, and hence the domain wall contributions to dielectric loss, will degrade the tunable performance in the microwave region. In this work, residual ferroelectricity—a persistent ferroelectric response above the global phase transition temperature—was characterized in tunable dielectrics using Rayleigh analysis. Chemical solution deposited Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} films, with relative tunabilities of 86% over 250 kV/cm at 100 kHz, demonstrated residual ferroelectricity 65 °C above the ostensible paraelectric transition temperature. Frequency dispersion observed in the dielectric temperature response wasmore » consistent with the presence of nanopolar regions as one source of residual ferroelectricity. The application of AC electric field for the Rayleigh analysis of these samples led to a doubling of the dielectric loss for fields over 10 kV/cm at room temperature.« less
  • Abstract not provided.
  • Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} (BST) films were deposited by pulsed laser deposition on copper foils with low-temperature self-buffered layers. The deposition conditions included a low oxygen partial pressure and a temperature of 700 C to crystallize the films without the formation of secondary phases and substrate oxidation. The results from x-ray diffraction and scanning electron microscopy indicated that the microstructure of the BST films strongly depended on the growth temperature. The use of the self-buffered layer improved the dielectric properties of the deposited BST films. The leakage current density of the BST films on the copper foil was 4.4 xmore » 10{sup -9} A cm{sup -2} and 3.3 x 10{sup -6} A cm{sup -2} with and without the self-buffered layer, respectively. The ferroelectric hysteresis loop for the BST thin film with buffer layer was slim, in contrast to the distorted loop observed for the film without the buffer layer. The permittivity (7 0 0) and dielectric loss tangent (0.013) of the BST film on the copper foil with self-buffered layer at room temperature were comparable to those of the film on metal and single-crystal substrates.« less