TY - GEN
T1 - High-Order Sezawa Mode Alscn/Gan/Sapphire Surface Acoustic Wave Resonators
AU - Zheng, Yue
AU - Wang, Jialin
AU - Park, Mingyo
AU - Wang, Ping
AU - Wang, Ding
AU - Mi, Zetian
AU - Ansari, Azadeh
N1 - Publisher Copyright:
© 2022 IEEE.
PY - 2022
Y1 - 2022
N2 - This work reports on the first demonstration of surface acoustic wave (SAW) resonators based on epitaxial aluminum scandium nitride (AlScN) on gallium nitride (GaN)/sapphire multilayer structure operating at 3-6 GHz. Al0.8Sc0.2N epitaxial films are grown on GaN/sapphire with molecular beam epitaxy (MBE). Interdigital transducers with submicron pitch sizes are patterned with electron beam lithography (EBL). With the highly piezoelectric AlScN epi-layer, high quality (Q) factor, high-order Sezawa modes are for the first time probed in an epi-AlScN/GaN/sapphire structure, exhibiting a Bode Q factor of 571 at 4.6 GHz. On the same epitaxial stack, ferroelectric polarization switching of Al0.8Sc0.2N is demonstrated, opening monolithic integration opportunities for acoustic resonators and ferroelectric capacitors. Corroborated with COMSOL ulations, the frequency response of the epi-AlScN/GaN/sapphire SAW resonator show enhanced piezoelectric response versus the GaN/sapphire resonator. The phase velocity versus the normalized thickness of Al0.8Sc0.2N of each propagation mode is analyzed and compared with the experimental values. Furthermore, the temperature coefficient of frequency (TCF) for each mode is evaluated from the temperature-dependent frequency response, showing a stable value around -30 ppm/K up to 600 K. The thermal stability of the epi-films makes them a great candidate for high temperature applications.
AB - This work reports on the first demonstration of surface acoustic wave (SAW) resonators based on epitaxial aluminum scandium nitride (AlScN) on gallium nitride (GaN)/sapphire multilayer structure operating at 3-6 GHz. Al0.8Sc0.2N epitaxial films are grown on GaN/sapphire with molecular beam epitaxy (MBE). Interdigital transducers with submicron pitch sizes are patterned with electron beam lithography (EBL). With the highly piezoelectric AlScN epi-layer, high quality (Q) factor, high-order Sezawa modes are for the first time probed in an epi-AlScN/GaN/sapphire structure, exhibiting a Bode Q factor of 571 at 4.6 GHz. On the same epitaxial stack, ferroelectric polarization switching of Al0.8Sc0.2N is demonstrated, opening monolithic integration opportunities for acoustic resonators and ferroelectric capacitors. Corroborated with COMSOL ulations, the frequency response of the epi-AlScN/GaN/sapphire SAW resonator show enhanced piezoelectric response versus the GaN/sapphire resonator. The phase velocity versus the normalized thickness of Al0.8Sc0.2N of each propagation mode is analyzed and compared with the experimental values. Furthermore, the temperature coefficient of frequency (TCF) for each mode is evaluated from the temperature-dependent frequency response, showing a stable value around -30 ppm/K up to 600 K. The thermal stability of the epi-films makes them a great candidate for high temperature applications.
UR - https://www.scopus.com/pages/publications/85126392982
UR - https://www.scopus.com/pages/publications/85126392982#tab=citedBy
U2 - 10.1109/MEMS51670.2022.9699728
DO - 10.1109/MEMS51670.2022.9699728
M3 - Conference contribution
AN - SCOPUS:85126392982
T3 - Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)
SP - 1046
EP - 1049
BT - 35th IEEE International Conference on Micro Electro Mechanical Systems Conference, MEMS 2022
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 35th IEEE International Conference on Micro Electro Mechanical Systems Conference, MEMS 2022
Y2 - 9 January 2022 through 13 January 2022
ER -