This paper presents a novel approach employing localized annealing through Joule heating to enhance the performance of Thin-Film Piezoelectric-on-Silicon (TPoS) MEMS resonators that are crucial for applications in sensing, energy harvesting, frequency filtering, and timing control. Despite recent advancements, piezoelectric MEMS resonators still suffer from anchor-related energy losses and limited quality factors (Qs), posing significant challenges for high-performance applications. This study investigates interface modification to boost the quality factor (Q) and reduce the motional resistance, thus improving the electromechanical coupling coefficient and reducing insertion loss. To balance the trade-off between device miniaturization and performance, this work uniquely applies DC current-induced localized annealing to TPoS MEMS resonators, facilitating metal diffusion at the interface. This process results in the formation of platinum silicide, modifying the resonator’s stiffness and density, consequently enhancing the acoustic velocity and mitigating the side-supporting anchor-related energy dissipations. Experimental results demonstrate a Q-factor enhancement of over 300% (from 916 to 3632) and a reduction in insertion loss by more than 14 dB, underscoring the efficacy of this method for reducing anchor-related dissipations due to the highest annealing temperature at the anchors. The findings not only confirm the feasibility of Joule heating for interface modifications in MEMS resonators but also set a foundation for advancements of this post-fabrication thermal treatment technology. 
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                            CMOS integrated ZnO thin film bulk acoustic resonator with Si3N4 susceptor layer for improved IR sensitivity
                        
                    
    
            Microelectromechanical sensors (MEMS) offer a new way of measuring temperature and infrared (IR) radiation, through measurements of total optical energy, overcoming the obstacles associated with narrow bandgap semiconductor detectors[1]. Specifically, Thin Film Bulk Acoustic Resonators (FBAR) offers a versatile MEMS technology based on resonant devices fabricated using piezoelectric materials [2]. With the addition of an absorbing susceptor and the use of zinc oxide (ZnO) as the piezoelectric it is possible to obtain a higher sensitivity device than previously demonstrated systems, taking advantage of ZnO's higher temperature coefficient of frequency (TCF) [3,4,5]. This work studies the improved sensing ability of an FBAR structure and ease of testing and superior parasitic performance provided in a package using an engineered high TCF FBAR in a monolithically integrated CMOS process. 
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                            - Award ID(s):
- 1343282
- PAR ID:
- 10053670
- Date Published:
- Journal Name:
- Device Research Conference
- Volume:
- 1
- Issue:
- 1
- Page Range / eLocation ID:
- 1 to 2
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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