A Solidly Mounted Resonator Fabricated by LiNbO3 Single-Crystalline Film on Flexible Polyimide Substrate

Shitian Huang; Wenbo Luo; Xiaoyuan Bai; Lu Lv; Xinqiang Pan; Yao Shuai; Chuangui Wu; Wanli Zhang

doi:10.1109/TUFFC.2021.3066589

A Solidly Mounted Resonator Fabricated by LiNbO₃ Single-Crystalline Film on Flexible Polyimide Substrate

IEEE Trans Ultrason Ferroelectr Freq Control. 2021 Jul;68(7):2585-2589. doi: 10.1109/TUFFC.2021.3066589. Epub 2021 Jun 29.

Authors

Shitian Huang, Wenbo Luo, Xiaoyuan Bai, Lu Lv, Xinqiang Pan, Yao Shuai, Chuangui Wu, Wanli Zhang

PMID: 33729935
DOI: 10.1109/TUFFC.2021.3066589

Abstract

A solidly mounted resonator on flexible polyimide (PI) substrate with high-effective coupling coefficient ( K_t² ) of 14.06% is reported in this article. This high K_t² is resulting from the LiNbO₃ (LN) single-crystalline film and [SiO₂/Mo]³ Bragg reflector. The quality of LN film fabricated by the crystal-ion-slicing (CIS) technique using benzocyclobutene (BCB) bonding layer was close to the bulk crystalline LN. The interfaces of the Al/LN/Al/[SiO₂/Mo]³ Bragg reflector/BCB/PI multilayer are sharp, and the thickness of each layer is consistent with its design value. The resonant frequency and K_t² keep stable when it is bent at different radii. These results demonstrate a feasible approach to realizing RF filters on flexible polymer substrates, which is an indispensable device for building integrated and multifunctional wireless flexible electronic systems.