Visible to the public A Review of the Approaches to Improve The Effective Coupling Coefficient of AlN based RF MEMS Resonators

TitleA Review of the Approaches to Improve The Effective Coupling Coefficient of AlN based RF MEMS Resonators
Publication TypeConference Paper
Year of Publication2020
AuthorsZhu, Y., Wang, N., Liu, C., Zhang, Y.
Conference Name2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)
Keywords2D lateral wave, acoustic coupling, acoustic resonators, AlN, aluminium compounds, Aluminum Nitride, bulk acoustic wave devices, communication applications, Couplings, crystal resonators, effective coupling coefficient, Human Behavior, III-V semiconductor materials, III-V semiconductors, Lateral wave, Micromechanical devices, micromechanical resonators, nonbulk acoustic wave aluminum nitride, Optical filters, piezoelectric MEMS resonators, pubcrawl, radiofrequency filters, Resiliency, resonator, Resonator filters, Resonators, RF MEMS, RF MEMS resonators, Scalability, two-dimensional lateral wave, vertical wave, wide band gap semiconductors
AbstractThis work reviews various methods which improve the effective coupling coefficient ( k2eff) of non-bulk acoustic wave (BAW) aluminum nitride (AlN) based RF MEMS resonators, mainly focusing on the innovative structural design of the resonators. k2eff is the key parameter for a resonator in communication applications because it measures the achievable fractional bandwidth of the filter constructed. The resonator's configuration, dimension, material stack and the fabrication process will all have impact on its k2eff. In this paper, the authors will review the efforts in improving the k2eff of piezoelectric MEMS resonators from research community in the past 15 years, mainly from the following three approaches: coupling lateral wave with vertical wave, exciting two-dimensional (2-D) lateral wave, as well as coupling 2-D lateral wave with vertical wave. The material will be limited to AlN family, which is proven to be manageable for manufacturing. The authors will also try to make recommendations to the effectiveness of various approaches and the path forward.
Citation Keyzhu_review_2020