Area Dependence of Effective Electromechanical Coupling Coefficient Induced by On-Chip Inductance in LiNbO3-Based BAW Resonators

Abstract

To solve the problem of filter bandwidth in 5G communication, it is urgent to develop an acoustic resonator with a large effective electromechanical coupling coefficient (Keff2). In this paper, the dependence between the resonance area and the performance of the bulk acoustic wave (BAW) resonator is studied. The solidly mounted resonators (SMRs) based on 43° Y cut lithium niobate (LN) were fabricated by the wafer transfer technique. The on-chip inductor was integrated with the BAW resonator through a pad electrode. Resonators with different resonant areas were fabricated and tested. Finite element modeling (FEM) simulation of acoustic resonators and electromagnetic (EM) simulation of layout were carried out, respectively. The Modified Butterworth Van Dyke (MBVD) model was used to analyze the results, and simulation of the Mason model was adopted. The results show that the dependency relationship between the resonant area and the effective electromechanical coupling coefficient can be induced by on-chip inductance. In the resonant area range of 20 × 20 μm2~160 × 160 μm2, the Keff2 increases from 11.97% to 43.28%.

LiNbO3 Surface Acoustic Wave Resonators with Large Effective Electromechanical Coupling

“…Furthermore, the random distribution of grain and the grain boundary in polycrystalline or amorphous films results in the reduction of the SAW performance. The crystal-ion-slicing (CIS) technology has been reported in our previous work [20][21][22]. High quality single crystalline and arbitrarily cut angle LNO film can be prepared.…”

Designed Structures of Interdigital Electrodes for Thin Film SAW Devices

“…Surface acoustic wave and bulk acoustic wave (BAW) resonators are broadly utilized in the filter units of the RF front-end of wireless communication due to their small package area and high-quality factor (Q) value [1][2][3][4]. BAW resonators have the ability to modify the working frequency by adjusting the thickness of the piezoelectric film, making them extensively used in frequency bands above 3.5 GHz [5,6]; the schematic diagram is shown in Figure 1a. BAW resonators have several advantages such as concentrated acoustic energy, low loss, and high-power capacity [7], but they require a long development period, involve numerous production process steps, and are ultimately costly.…”

Epitaxial ZnO piezoelectric layer on SiO2/Mo solidly mounted resonator fabricated using epitaxial Au sacrificial layer

“…BAW filters based on LiNbO 3 and LiTaO 3 thin films by cutting from their bulk single crystals have been reported. [2][3][4][5][6][7][8][9][10][11][12][13] While sputtered AlN thin films can be mass-produced at 8 inches in a bottom-up process, bulk single crystals such as LiNbO 3 and LiTaO 3 are limited to 6 inches. On the other hand, by using an epitaxial growth technique, the fabrication of single crystalline AlN and ScAlN thin films over 8 inches might not even be difficult and can be relatively easily fabricated.…”