High Frequency Solidly Mounted Resonator Using LN Single Crystal Thin Plate

In this study, the solidly mounted resonators (SMRs) using the thickness expansion (TE) mode of LiNbO3 (LN) single crystal thin plate were investigated. The dispersion curves of the rotated Y-LN plate were drawn by plotting the admittance calculated by FEM. From the calculated dispersion curves, the vibration mode and the energy trapping were confirmed. An SMR composed of an Al electrode, a 1 μm thick 20°Y-LN single crystal plate, an acoustic multilayer and a Si substrate was fabricated. TE mode with 7.1% bandwidth and 34.3 dB impedance ratio was observed at 3.2 GHz. 1.7 GHz thickness shear (TS) mode response was also excited since the fabricated 20°Y-LN SMR was not optimized in terms of the Euler angle of LN. The frequency characteristics could be improved by optimizing the Euler angle and electrode structures.