Electromechanical coupling coefficient for surface acoustic waves in single-crystal bulk aluminum nitride

2004 ◽  
Vol 84 (23) ◽  
pp. 4611-4613 ◽  
Author(s):  
G. Bu ◽  
D. Ciplys ◽  
M. Shur ◽  
L. J. Schowalter ◽  
S. Schujman ◽  
...  
Keyword(s):  
Aluminum Nitride ◽  
Single Crystal ◽  
Coupling Coefficient ◽  
Acoustic Waves ◽  
Electromechanical Coupling ◽  
Surface Acoustic Waves ◽  
Electromechanical Coupling Coefficient ◽  
Crystal Bulk

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.

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.

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.

Surface Acoustic Waves And Guided Optical Waves In AlGaN Films

2003 ◽  
Vol 764 ◽  
Author(s):  
Gang Bu ◽  
Daumantas Ciplys ◽  
Michael Shur ◽  
Remis Gaska ◽  
Qhalid Fareed ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Acoustic Waves ◽  
Electromechanical Coupling ◽  
Surface Acoustic Waves ◽  
Molar Fraction ◽  
Electromechanical Coupling Coefficient ◽  
Optical Wave ◽  
Optical Waves ◽  
Wide Range

AbstractAlxGa1-xN layers grown by MOCVD on sapphire substrates have been tested using the surface acoustic wave and guided optical wave techniques. Samples with molar fraction of Al up to 0.36 have been investigated. The parameters S11 of single surface acoustic wave transducers and S12 of two-port devices have been measured with the network analyzer. The values of the surface acoustic wave velocity and electromechanical coupling coefficient for the layer-substrate structure have been extracted and calculated using material parameters available from literature. The attenuation of guided optical waves along the propagation track in AlxGa1-xN layers has been measured using the CCD imaging technique. The attenuation dependence on the mode order and layer thickness has been studied. Our results show that the properties of AlxGa1-xN that determine surface acoustic wave and guided optical wave propagation are similar to the properties of GaN films within a relatively wide range of x up to x =0.36.

Sign in / Sign up

Export Citation Format

Share Document