Improvement of surface acoustic wave characteristics of ZnO film/interdigital transducer/glass substrate using alumina film interlayer

ZnO films with c-axis (0002) orientation have been successfully grown by RF magnetron sputtering on Al2O3/glass substrates. The alumina films were firstly deposited on glass substrates, and then secondly deposited on interdigital transducer/ZnO film/alumina film/glass substrates by electron beam evaporation. The crystalline structure and surface roughness of the films were investigated by X-ray diffraction and atomic force microscopy, respectively. The phase velocity and coupling coefficient of the surface acoustic wave (SAW) device were both increased when we deposited the double alumina layers. On the other hand, the temperature coefficient of frequency becomes better if we increase the thickness of the lower alumina film. The experimental result is beneficial for improving the performance of the ZnO thin-film SAW devices on inexpensive glass substrates.

Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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Improving the properties of zinc oxide thin-film surface acoustic wave device on glass substrate by introducing double alumina layers

Shih¹,

Huang²,

Wu³

2017

“…With the spread of mobile communication apparatus, further improvement of the characteristics of surface acoustic wave (SAW) devices is required. In particular, to obtain a highfrequency, driving stationarity with temperature, and a high electromechanical coupling factor, substrate structures such as thin film loading structures, [1][2][3][4][5][6][7][8][9][10] bonded structures between material substrates, [11][12][13] and multilayered structures 14) have been studied. Along with these studies, accurate evaluation of the acoustical losses of substrate materials and loaded thin films is required to design SAW devices.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of SiO₂ Thin films on piezoelectric substrates using line-focus-beam ultrasonic material characterization system

Suenaga

Suzuki

Kakio

et al. 2019

SiO2 thin films deposited on LiNbO3 and LiTaO3 using RF magnetron sputtering were evaluated using a line-focus-beam ultrasonic material characterization (LFB-UMC) system. From the measured velocity of a leaky surface acoustic wave (LSAW), c11 and c44 for a SiO2 film were determined to be 0.755 × 1011 and 0.289 × 1011 N m−2 assuming that the density and dielectric constant of the thin film were bulk values. The measured LSAW velocities are in good agreement with values calculated using determined values. The acoustical loss was evaluated from the difference between the measured propagation attenuation and the calculated leakage loss into water. However, the differences were 0.02–0.27 dB/λ, which were considered to be too large for the acoustical loss of SiO2 thin films. By accurately measuring the density of a thin film and determining its elastic constant, it is possible that the acoustical loss of a thin film can be evaluated using an LFB-UMC system.

“…With the spread of mobile communication apparatus, further improvement of the characteristics of surface acoustic wave (SAW) devices is required. In particular, to obtain a high frequency, driving stationarity with temperature, and a high electromechanical coupling factor, substrate structures such as thin-film loading structures [1][2][3][4][5][6][7][8][9][10][11][12] and bonding structures between material substrates 13,14) have been studied. Along with these studies, the accurate evaluation of the acoustical losses of substrate materials and loaded thin films is required to design SAW devices.…”

Section: Introductionmentioning

confidence: 99%

Propagation properties of leaky surface acoustic wave on water-loaded piezoelectric substrate

Suenaga

Suzuki

Kakio

et al. 2018

To evaluate acoustical loss mainly due to Rayleigh scattering loss of a thin film material using a line-focus-beam ultrasonic material characterization system, surface acoustic waves (SAWs) were excited and detected using IDTs, the propagation properties of SAWs with and without water loading were measured, and the acoustical losses of amorphous SiO2 and Ta2O5 thin films deposited on 128°YX-LiNbO3 were evaluated by subtracting the calculated attenuation of leakage loss into water from the measured propagation loss of leaky SAWs (LSAWs) on water-loaded specimens. The results of the evaluation of acoustical losses using LSAWs with the SAW propagation mode of the small leakage loss were in good agreement with the measured propagation loss of the Rayleigh-type SAW corresponding to the acoustical loss.