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W. Wang, P.M. Mayrhofer, X. He, A. Bittner, U. Schmid, J. Luo:
"High performance AlScN thin film based surface acoustic wave devices with large electromechanical coupling coefficient";
Applied Physics Letters, 105 (2014), 133502-1.

AlN and AlScN thin films with 27% scandium (Sc) were synthesized by DC magnetron sputtering deposition and used to fabricate surface acoustic wave (SAW) devices. Compared with AlN-based devices, the AlScN SAW devices exhibit much better transmission properties. Scandium doping
results in electromechanical coupling coefficient, K2, in the range of 2.0% 2.2% for a wide normalized thickness range, more than a 300% increase compared to that of AlN-based SAW devices, thus demonstrating the potential applications of AlScN in high frequency resonators, sensors, and
high efficiency energy harvesting devices. The coupling coefficients of the present AlScN based SAW devices are much higher than that of the theoretical calculation based on some assumptions for AlScN piezoelectric material properties, implying there is a need for in-depth investigations on
the material properties of AlScN.

AlN and AlScN thin films with 27% scandium (Sc) were synthesized by DC magnetron sputtering deposition and used to fabricate surface acoustic wave (SAW) devices. Compared with AlN-based devices, the AlScN SAW devices exhibit much better transmission properties. Scandium doping
results in electromechanical coupling coefficient, K2, in the range of 2.0% 2.2% for a wide normalized thickness range, more than a 300% increase compared to that of AlN-based SAW devices, thus demonstrating the potential applications of AlScN in high frequency resonators, sensors, and
high efficiency energy harvesting devices. The coupling coefficients of the present AlScN based SAW devices are much higher than that of the theoretical calculation based on some assumptions for AlScN piezoelectric material properties, implying there is a need for in-depth investigations on
the material properties of AlScN.

http://dx.doi.org/10.1063/1.4896853

Project Head Ulrich Schmid:
Mikrosystemtechnik Projektkonto Schmid