A High- k^ Switchable Ferroelectric Al0.7Sc0.3N Film Bulk Acoustic Resonator

This work demonstrates the hysteresis behavior and temperature characterization of an AlScN Film bulk acoustic resonator (FBAR) with ∼30% \text{Sc}/(\text{Al}+\text{Sc}) ratio. Operating at ∼3 GHz, the as-fabricated FBAR exhibits a record high effective electromechanical coupling ( k_{t}{}^{2} ) of...

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Bibliographic Details
Main Authors: Wang, Jialin, Park, Mingyo, Mertin, Stefan, Pensala, Tuomas, Ayazi, Farrokh, Ansari, Azadeh
Format: Conference Proceeding
Language:English
Subjects:
Acoustic resonators
Aluminum Scandium Nitride
FBAR
Ferroelectric
Filters
Frequency tuning
Piezoelectric films
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Summary:This work demonstrates the hysteresis behavior and temperature characterization of an AlScN Film bulk acoustic resonator (FBAR) with ∼30% \text{Sc}/(\text{Al}+\text{Sc}) ratio. Operating at ∼3 GHz, the as-fabricated FBAR exhibits a record high effective electromechanical coupling ( k_{t}{}^{2} ) of 18% with a mechanical quality factor ( Q_{m} ) of 328. The polarization of the FBAR can be switched from N-polar to Al-polar by using a triangular-wave signal with a peak voltage of −350 V, applied for 6 seconds at 1 kHz across a 900 nm-thick Al 0.7 Sc 0.3 N film. It is shown that the polarization switching of AlScN film not only changes the polarity of the piezoelectric coefficient (e 33 ), but also changes the series resistance of the metal-ferroelectric-metal (MFM) stack and leads to an effective "switching" of the FBAR. The frequency response of the switchable FBAR is investigated after polarization switching during 4 cycles and at elevated temperatures up to 600 K.
ISSN:2375-0448
DOI:10.1109/IFCS-ISAF41089.2020.9234831