Electromechanical coupling coefficient for surface acoustic waves in proton-exchanged 128°-rotated Y-cut lithium niobate

1998 ◽  
Vol 73 (17) ◽  
pp. 2417-2419 ◽  
Author(s):  
D. Čiplys ◽  
R. Rimeika
Keyword(s):  
Lithium Niobate ◽  
Coupling Coefficient ◽  
Acoustic Waves ◽  
Electromechanical Coupling ◽  
Surface Acoustic Waves ◽  
Electromechanical Coupling Coefficient

Properties of Surface Acoustic Waves in AlN And GaN

2002 ◽  
Vol 743 ◽  
Author(s):  
Jianyu Deng ◽  
Daumantas Ciplys ◽  
Gang Bu ◽  
Michael Shur ◽  
Remis Gaska
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Coupling Coefficient ◽  
Acoustic Waves ◽  
Electromechanical Coupling ◽  
Surface Acoustic Waves ◽  
Elastic Displacement ◽  
Electromechanical Coupling Coefficient ◽  
Coupling Coefficients ◽  
Calculation Results

ABSTRACTThe surface acoustic wave velocities, electromechanical coupling coefficients, and the spatial distributions of both elastic displacement and electric potential have been calculated for various configurations of gallium nitride and aluminum nitride. The electromechanical coupling coefficient values of 0.13 % in GaN and 0.29 % in AlN have been predicted. The maximum electromechanical coupling coefficient values of 0.24 % at Euler angles (0, 54°, 90°) in GaN and 1.08 % at (0, 53°, 90°) in AlN have been found. For GaN layer-on- sapphire substrate structures, the SAW velocity and electromechanical coupling coefficient have been calculated as functions of layer thickness and acoustic wavelength. The experimentally measured values of the surface acoustic wave velocity and electromechanical coupling coefficient are in satisfactory agreement with the calculation results.

LEAKY SURFACE ACOUSTIC WAVES IN SINGLE-CRYSTAL AlN SUBSTRATE

2004 ◽  
Vol 14 (03) ◽  
pp. 837-846 ◽  
Author(s):  
GANG BU ◽  
DAUMANTAS CIPLYS ◽  
MICHAEL S. SHUR ◽  
LEO J. SCHOWALTER ◽  
SANDRA B. SCHUJMAN ◽  
...  
Keyword(s):  
Single Crystal ◽  
Acoustic Waves ◽  
Electromechanical Coupling ◽  
Surface Acoustic Waves ◽  
Propagation Direction ◽  
Electromechanical Coupling Coefficient ◽  
Coupling Coefficients ◽  
Leaky Waves ◽  
Temperature Coefficient Of Frequency ◽  
Piezoelectric Constants

We report on the velocity V and the electromechanical coupling coefficient K2 of the first and the second leaky surface acoustic waves in various propagation directions in the a-plane AlN single-crystal. For c-propagation direction, the second leaky wave exhibited the velocity of 11016 m/s and K2 of 0.45%. For this direction, the temperature coefficient of frequency was found to be -30 ppm/°C. A near match of the velocities of the plane and leaky waves in the a-plane AlN allowed us to establish analytical relationships between the piezoelectric and elastic constants. A full set of elastic and piezoelectric constants of AlN has been evaluated by fitting the measured and calculated dependencies of velocities and electromechanical coupling coefficients on the propagation direction for both Rayleigh and leaky waves.

scholarly journals Epitaxial Growth of Sc0.09Al0.91N and Sc0.18Al0.82N Thin Films on Sapphire Substrates by Magnetron Sputtering for Surface Acoustic Waves Applications

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4630
Author(s):  
Florian Bartoli ◽  
Jérémy Streque ◽  
Jaafar Ghanbaja ◽  
Philippe Pigeat ◽  
Pascal Boulet ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Electromechanical Coupling ◽  
Surface Acoustic Waves ◽  
Electromechanical Coupling Coefficient ◽  
X Ray Diffraction ◽  
Plasma Parameters ◽  
Sapphire Substrates ◽  
Saw Devices ◽  
Transmission Electron ◽  
Electrical Characterizations

Scandium aluminum nitride (ScxAl1-xN) films are currently intensively studied for surface acoustic waves (SAW) filters and sensors applications, because of the excellent tradeoff they present between high SAW velocity, large piezoelectric properties and wide bandgap for the intermediate compositions with an Sc content between 10 and 20%. In this paper, the growth of Sc0.09Al0.91N and Sc0.18Al0.82N films on sapphire substrates by sputtering method is investigated. The plasma parameters were optimized, according to the film composition, in order to obtain highly-oriented films. X-ray diffraction rocking-curve measurements show a full width at half maximum below 1.5°. Moreover, high-resolution transmission electron microscopy investigations reveal the epitaxial nature of the growth. Electrical characterizations of the Sc0.09Al0.91N/sapphire-based SAW devices show three identified modes. Numerical investigations demonstrate that the intermediate compositions between 10 and 20% of scandium allow for the achievement of SAW devices with an electromechanical coupling coefficient up to 2%, provided the film is combined with electrodes constituted by a metal with a high density.

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