Electrically tunable microwave devices prepared by rf-magnetron sputtering

Author

Gibbons, B.J. ; Findikoglu, A.T. ; Jia, Q.X. ; Reagor, D.W.

Author_Institution

Supercond. Technol. Center, Los Alamos Nat. Lab., NM, USA

Volume

1

fYear

2000

fDate

2000

Firstpage

201

Abstract

In this work, we have used the Warren-Averbach method to analyze the x-ray diffraction patterns of several Ba_0.6Sr_0.4TiO₃ (BST) epitaxial thin films deposited via 90° off-axis rf-magnetron sputtering. This method allows for the determination of the coherent strains, incoherent strains, crystallite sizes, and defect densities in these films. Results indicate that for BST (60/40) films, the incoherent strain normal to the substrate is smaller on LAO compared to MgO for films 200 Å - 3000 Å thick. However, the opposite relationship holds for the coherent strains. The thickest films showed dielectric constants of 1350 and 925 on MgO and LAO, respectively (at 1 MHz). All showed dielectric loss on the order of 0.007 with the room temperature tunability being 3 times greater for the films on MgO. In-plane measurements of the coherent strain were also completed, showing good agreement with theoretical predictions of the effects of strain on the dielectric properties

Keywords

X-ray diffraction; dielectric losses; ferroelectric capacitors; ferroelectric thin films; microwave devices; microwave materials; permittivity; sputter deposition; sputtered coatings; thin film capacitors; tuning; 200 to 3000 A; Ba_0.6SrO₄TiO₃; Warren-Averbach method; capacitors; coherent strains; conformal mapping model; crystallite sizes; defect densities; dielectric constants; dielectric loss; electrically tunable microwave devices; epitaxial thin films; incoherent strains; lattice parameters; off-axis RF-magnetron sputtering; room temperature tunability; x-ray diffraction patterns; Binary search trees; Capacitive sensors; Dielectric losses; Dielectric substrates; Microwave devices; Pattern analysis; Sputtering; Strain measurement; Strontium; X-ray diffraction;

fLanguage

English

Publisher

ieee

Conference_Titel

Applications of Ferroelectrics, 2000. ISAF 2000. Proceedings of the 2000 12th IEEE International Symposium on

Conference_Location

Honolulu, HI

ISSN

1099-4734

Print_ISBN

0-7803-5940-2

Type

conf

DOI

10.1109/ISAF.2000.941541

Filename

941541