Correlations between microstructure and Q-factor of tunable thin film bulk acoustic wave resonators
Journal article, 2011

Correlations between microstructure and Q-factor of tunable solidly mounted Ba(0.25)Sr(0.75)TiO(3) (BSTO) thin film bulk acoustic wave resonators are studied using analysis of test structures prepared at different growth temperatures of the BSTO films varying in the range 450-650 degrees C. The observed changes in the Q-factor with growth temperature are correlated with related changes in microstructure, including the grain size, texture misalignment, interfacial amorphous layer, surface roughness, and deterioration of the Bragg reflector layers. The correlations are established through analysis of corresponding extrinsic acoustic loss mechanisms, including Rayleigh scattering at localized defects, acoustic attenuation by amorphous layer, generation of the shear waves leaking into the substrate, waves scattering by surface roughness, and resonance broadening by local thickness variations. It is shown that the waves scattering by surface roughness at the BSTO film interfaces is the main loss mechanism limiting the Q-factor of the BSTO thin film bulk acoustic wave resonators. (C) 2011 American Institute of Physics. [doi:10.1063/1.3626939]

relaxation

devices

ferroelectrics

electrodes

deposition

capacitors

Author

Andrei Vorobiev

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

Spartak Gevorgian

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

Markus Löffler

Chalmers, Applied Physics, Microscopy and Microanalysis

Eva Olsson

Chalmers, Applied Physics, Microscopy and Microanalysis

Journal of Applied Physics

0021-8979 (ISSN) 1089-7550 (eISSN)

Vol. 110 5 054102

Subject Categories

Physical Sciences

DOI

10.1063/1.3626939