The effective electromechanical coupling coefficient of piezoelectric thin-film resonators

2005 ◽  
Vol 86 (2) ◽  
pp. 022904 ◽  
Author(s):  
Qingming Chen ◽  
Qing-Ming Wang
Keyword(s):  
Thin Film ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Electromechanical Coupling Coefficient ◽  
Piezoelectric Thin Film ◽  
Thin Film Resonators ◽  
Effective Electromechanical Coupling Coefficient

scholarly journals Fabrication of a 3.5-GHz Solidly Mounted Resonator by Using an AlScN Piezoelectric Thin Film

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1151
Author(s):  
Chan-Yu Chung ◽  
Ying-Chung Chen ◽  
Yu-Cheng Chen ◽  
Kuo-Sheng Kao ◽  
Yu-Chen Chang
Keyword(s):  
Thin Film ◽  
Resonance Frequency ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Bragg Reflector ◽  
Electromechanical Coupling Coefficient ◽  
Axis Orientation ◽  
X Ray ◽  
Aln Film ◽  
Piezoelectric Thin Film

In this study, a 3.5-GHz solidly mounted resonator (SMR) was developed by doping scandium in aluminum nitride to form AlScN as the piezoelectric thin film. Molybdenum (Mo) of 449 nm thickness and silicon dioxide (SiO2) of 371 nm thickness were used as the high and low acoustic impedance films, respectively, which were alternately stacked on a silicon substrate to form a Bragg reflector. Then, an alloy target with atomic ratio of 15% Sc was adopted to deposit the piezoelectric AlScN thin film on the Bragg reflector, using a radio frequency magnetron sputtering system. The characteristics of the c-axis orientation of the AlScN thin films were optimized by adjusting sputtering parameters as sputtering power of 250 W, sputtering pressure of 20 mTorr, nitrogen gas ratio of 20%, and substrate temperature of 300 °C. Finally, a metal top electrode was coated to form a resonator. The X-ray diffraction (XRD) analysis showed that the diffraction peak angles of the AlScN film shifted towards lower angles in each crystal phase, compared to those of AlN film. The energy dispersive X-ray spectrometer (EDX) analysis showed that the percentage of scandium atom in the film is about 4.5%, regardless of the sputtering conditions. The fabricated resonator exhibited a resonance frequency of 3.46 GHz, which was a small deviation from the preset resonance frequency of 3.5 GHz. The insertion loss of −10.92 dB and the electromechanical coupling coefficient of 2.24% were obtained. As compared to the AlN-based device, the AlScN-based resonator exhibited an improved electromechanical coupling coefficient by about two times.

Characteristics Analysis of Saw Filter Using Al0.36Ga0.64N Thin Film

2002 ◽  
Vol 720 ◽  
Author(s):  
Sun-Ki Kim ◽  
Min-Jung Park ◽  
Cheol-Yeong Jang ◽  
Hyun-Chul Choi ◽  
Jung-Hee Lee ◽  
...  
Keyword(s):  
Thin Film ◽  
Insertion Loss ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Side Lobe ◽  
Electromechanical Coupling Coefficient ◽  
Device Performance ◽  
Saw Devices ◽  
Characteristics Analysis ◽  
Temperature Coefficient Of Frequency

AbstractAlxGa1-xN sample with x=0.36 was epitaxially grown on sapphire by MOCVD. SAW velocity of 5420 m/s and TCF (temperature coefficient of frequency) of -51.20 ppm/°C were measured from the SAW devices fabricated on the AlxGa1-xN sample, when kh value was 0.078, at temperatures between –30 °C and 60 °C Electromechanical coupling coefficient was ranged from 1.26 % to 2.22 %. The fabricated SAW filter have shown a good device performance with insertion loss of -33.853 dB and side lobe attenuation of 20 dB.

scholarly journals Analysis on the Radial Vibration of Longitudinally Polarized Radial Composite Tubular Transducer

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4785
Author(s):  
Xiaoyu Wang ◽  
Shuyu Lin
Keyword(s):  
High Power ◽  
Coupling Coefficient ◽  
Piezoelectric Ceramic ◽  
Electromechanical Coupling ◽  
Electromechanical Coupling Coefficient ◽  
Radial Vibration ◽  
Resonance Frequencies ◽  
Second Mode ◽  
Radial Resonance ◽  
Effective Electromechanical Coupling Coefficient

The radial vibration of a radial composite tubular transducer with a large radiation range and power capacity is studied. The transducer is composed of a longitudinally polarized piezoelectric ceramic tube and a coaxial outer metal tube. Assuming that the longitudinal length is much larger than the radius, the electromechanical equivalent circuits of the radial vibration of a piezoelectric ceramic long tube and a metal long tube are derived and obtained for the first time following the plane strain theory. As per the condition of the continuous forces and displacements of two contact surfaces, the electromechanical equivalent circuit of the tubular transducer is obtained. The radial resonance/anti-resonance frequency equation and the expression of the effective electromechanical coupling coefficient are obtained. Then, the effects of the radial geometry dimension of the transducer on the vibration characteristics are analyzed. The theoretical resonance frequencies, anti-resonance frequencies, and the effective electromechanical coupling coefficients at the fundamental mode and the second mode are in good agreement with the finite element analysis (FEA) results. The study shows that when the overall size of the transducer is unchanged, as the proportion of piezoelectric ceramic increases, the radial resonance/anti-resonance frequency and the effective electromechanical coupling coefficient of the transducer at the fundamental mode and the second mode have certain characteristics. The radial composite tubular transducer is expected to be used in high-power ultrasonic wastewater treatment, ultrasonic degradation, and underwater acoustics, as well as other high-power ultrasonic fields.

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