The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
Tiancheng Luo
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
Zhiwei Wen
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
Min Wei
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
Xiyu Gu
Key Laboratory of Artificial Micro, and Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
Xiang Chen
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
Yang Zou
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
Yao Cai
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
Yan Liu
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
Chengliang Sun
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
The arrival of the 5G era has promoted the need for filters of different bandwidths. Thin-film bulk acoustic resonators have become the mainstream product for applications due to their excellent performance. The Keff2 of the FBAR greatly influences the bandwidth of the filter. In this paper, we designed an AlN-based adjustable Keff2 FBAR by designing parallel capacitors around the active area of the resonator. The parallel capacitance is introduced through the support column structure, which is compatible with conventional FBAR processes. The effects of different support column widths on Keff2 were verified by finite element simulation and experimental fabrication. The measured results show that the designed FBAR with support columns can achieve a Keff2 value that is 25.9% adjustable.
