Monolithic Integration of ScAlN MEMS Filter on RFSOI Using ALD Al2O3 as VHF Barrier

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Monolithic Integration of ScAlN MEMS Filter on RFSOI Using ALD Al2O3 as VHF Barrier
Title:
Monolithic Integration of ScAlN MEMS Filter on RFSOI Using ALD Al2O3 as VHF Barrier
Journal Title:
2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers)
DOI:
Publication Date:
07 May 2024
Citation:
X. Wang et al., "Monolithic Integration of ScAlN MEMS Filter on RFSOI Using ALD Al2O3 as VHF Barrier," 2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers), Kyoto, Japan, 2023, pp. 1240-1243.
Abstract:
We present a novel low-temperature process approach that enables the monolithic integration of scandium-doped aluminum nitride (ScAlN)-based radio frequency (RF) micro electromechanical system (MEMS) filters with RF switches. A planarized SiO 2 -based ankle and cavities for the MEMS device were established through a three-step process: 1) swimming pool pattern and etch, 2) passivation of the side wall and bottom of the swimming pool with atomic layer deposited Al 2 O 3 , and 3) swimming pool refill with SiO 2 and planarization. ScAlN film based bulk acoustic resonators (FBAR) filters were then fabricated on the planarized surface, and eventually undercut was formed using vapor hydrofluoric acid (VHF) etch. The highest process temperature is 350 °C in the whole integration flow. The approach enabled successful integration of a ScAlN-based MEMS filter on top of the radio-frequency integrated circuit switch wafer. The integrated FBAR shows a center operation frequency of 2.58 GHz, bandwidth of 117 MHz, and an insertion loss of 3.7 dB. The integrated filter with switch has a footprint of 1mm 2 .
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
Description:
© 2024 IEEE.  Personal use of this material is permitted.  Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
ISSN:
2167-0021
ISBN:
978-4-88686-435-2
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