Over the past several decades, the technology of micro-electromechanical system（MEMS） has advanced. A clear need of miniaturization and integration of electronics components has had new solutions for the next generation of wireless communications. The aluminum nitride（AlN） MEMS contour-mode resonator（CMR）has emerged and become promising and competitive due to the advantages of the small size, high quality factor and frequency, low resistance, compatibility with integrated circuit（IC） technology, and the ability of integrating multi-frequency devices on a single chip. In this article, a comprehensive review of AlN MEMS CMR technology will be presented, including its basic working principle, main structures, fabrication processes, and methods of performance optimization. Among these, the deposition and etching process of the AlN film will be specially emphasized and recent advances in various performance optimization methods of the CMR will be given through specific examples which are mainly focused on temperature compensation and reducing anchor losses. This review will conclude with an assessment of the challenges and future trends of the CMR.
This paper presents and analyzes a notch observed in MEMS （micro electric mechanical system） filter characterization using the difference method. The difference method takes advantage of the cancellation of parasitic feed-through, which could potentially obscure the relatively small motional signal and lead to failure in character- ization of the MEMS components. In this paper, typical clamped-clamped beam MEMS filters are fabricated and characterized with the difference method. Using the difference method a better performance is obtained but a notch is induced as a potential problem. Analysis is performed and reveals the mismatch of the two differential excitation signals in measurement circuit contributes to the notch. The relevant circuit design rule is also proposed to avoid the notch in the difference method.
