Liu, C., Qian, Y., Zhang, Y., Wang, X., Li, M., Liu, P., Lin, H., Zhang, Q., & Zhu, Y. (2024). Up to 48 GHz mmWave Ferroelectric SC0.3Al0.7N Bulk Acoustic Wave Resonators and Filters. 2024 IEEE International Electron Devices Meeting (IEDM), 1–4. https://doi.org/10.1109/iedm50854.2024.10873336
Abstract:
In this work, single-layer and bilayer mmWave bulk acoustic wave (BAW) resonators based on 40 nm thick ferroelectric SC0.3Al0.7N film were designed and demonstrated. A 5 nm transition layer with a gradient in Sc composition was implemented to improve the quality of 40 nm co-sputtered thin SC0.3Al0.7N film, resulting in 3 times improvement of effective coupling coefficient (k2eff) to > 13%, quality factor raised up to ~ 300, and 26-dB increment in impedance ratio (Rp/Rs) for the single-layer BAW resonator exceeding 20 GHz. Additionally, compact filters have been demonstrated with a central frequency at 21 GHz and a fractional bandwidth close to 11%, surpassing the performance metrics of reported ScAlN-based mmWave filters. With the 40 nm SC0.3Al0.7N integrated on 50 nm AlN film, a periodically poled bilayer resonator was realized by ferroelectric switching of SC0.3Al0.7N without the middle electrode, capable of alternating between frequencies in the mmWave spectrum (18.8 GHz and 48.3 GHz).
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the Science and Engineering Research Council of A*STAR - Ferroelectric Aluminum Scandium Nitride (Al1-xScxN) Thin Films and Devices for mm-Wave and Edge Computing
Grant Reference no. : A20G9b0135