High-acoustic-impedance tantalum oxide layers for insulating acoustic reflectors

J. Capilla, J. Olivares, M. Clement, J. Sangrador, E. Iborra, A. Devos
2012 IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control  
This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended for use as high-impedance films of acoustic reflectors for solidly mounted resonators operating in the gigahertz frequency range. The films are grown by sputtering a metallic tantalum target under different oxygen and argon gas mixtures, total pressures, pulsed dc powers, and substrate biases. The structural properties of the films are assessed through infrared absorption spectroscopy and
more » ... ay diffraction measurements. Their acoustic impedance is assessed by deriving the mass density from X-ray reflectometry measurements and the acoustic velocity from picosecond acoustic spectroscopy and the analysis of the frequency response of the test resonators.
doi:10.1109/tuffc.2012.2205 pmid:22481769 fatcat:xub3ytlekvbibmmrokeogfa77y