Achieving both high electromechanical response and stable temperature behavior in Si/SiO2/Al/LiTaO3 sandwich structure

et al. 2022

Micromachines

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To obtain a high-performance surface acoustic wave (SAW) gyroscope substrate, the propagation characteristics and gyroscopic effect of Rayleigh waves in a 128°Y–X LiNbO3/SiO2/Si (LNOI) functional substrate were investigated with a three-dimensional finite element method. The influence of LNOI structural parameters on Rayleigh wave characteristics, including the phase velocity (vp), electromechanical coupling coefficient (K2) and temperature coefficient of frequency (TCF), were analyzed. The results demonstrate that the SiO2 layer compensates for the negative TCF of 128°Y–X LiNbO3 and enhances the K2 of the LNOI substrate. The Rayleigh wave velocity change of the LNOI substrate after rotations in different directions was studied. The gyroscope gain factor (η) represents the strength of the gyroscopic effect in the differential traveling wave SAW gyroscope and is defined. The ηy and ηz of the LNOI substrate with different structural parameters were investigated. Finally, an LNOI substrate with an hLN/λ of 0.2 and an hSiO2/λ of 0.05 was obtained by balancing the characteristic parameters, with a K2 of 3.96%, TCF of −18.75 ppm/°C and ηy of 0.26. The LNOI substrate has a better gyroscopic effect and temperature stability than the 128°Y–X LiNbO3 crystal. The LNOI substrate meets device miniaturization and integration needs.

Section: Simulation Detailsmentioning

confidence: 99%

FEM Simulation of a High-Performance 128°Y–X LiNbO3/SiO2/Si Functional Substrate for Surface Acoustic Wave Gyroscopes

Liu

et al. 2022

Micromachines

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“…The amplitude of κ determines the width of the stopband. The lower and upper frequencies of the stopband f s+ and f s− can be obtained by considering the zeros of the dispersion relation [28,29]. Then, we have:…”

Section: Extraction Technique Of Com Parametersmentioning

confidence: 99%

Fast, Accurate and Full Extraction of Coupling-of-Modes Parameters by Finite Element Method

Zhou

et al. 2022

Crystals

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This paper presents a new numerical approach for the full extraction of the coupling-of-modes (COM) parameters by stationary and eigenfrequency analyses in the finite element method (FEM). This is a fast method extracting from the results of static analysis and eigenfrequency analysis. It avoids the long calculation time of admittance frequency response analysis, which is commonly used in extracting COM parameters. In addition to the usual COM parameters (velocity, reflection coefficient, transduction coefficient and capacitance), the phases of reflection and transduction coefficient can be also extracted with this method. The proposed method was applied to different cutting types LiNbO3 with different types of thicknesses in a varying interdigital transducer (IDT). These examples show that our approach has great potential in extracting all the COM parameters of the Rayleigh SAW for all kinds of IDT structures. Therefore, it is a fast, accurate, general and full extraction approach of COM parameters.

“…Taking 128°Y-X LN POS substrate as the simulation object, the model structure of IDT/LN/BCB/Si was established by COMSOL, as shown in Supplementary Figure S2. The detailed material constants are listed in Supplementary Table S1 (Sun et al, 2019).…”

Section: Saw Characteristics Of Pos Substratementioning

confidence: 99%

“…Nowadays, most of the SAW sensors are made on the piezoelectric crystal, which brings about difficulties in the integration and miniaturization (Lu et al, 2013;Mimura et al, 2017). Using a multilayer structure to prepare the SAW sensor is considered one of the most promising techniques (Moulet et al, 2008;Maouhoub et al, 2016;Tian et al, 2016;Sun et al, 2019;Naumenko, 2020). Since the piezoelectric-on-silicon (POS) substrate bonds the piezoelectric thin film on a silicon wafer, this structure can efficiently reduce the SAW sensor's volume and weight (Abdolvand et al, 2008;Ali and Lee, 2016).…”

Section: Introductionmentioning

confidence: 99%

In-Situ Process and Simulation of High-Performance Piezoelectric-on-Silicon Substrate for SAW Sensor

Liu

et al. 2021

Front. Mater.

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This paper studied the manufacturing process of Piezoelectric-on-Silicon (POS) substrate which integrates 128° Y–X Lithium niobate thin film and silicon wafer using Smart-Cut technology. The blistering and exfoliation processes of the He as-implanted LN crystal under different annealing temperatures are observed by the in-situ method. Unlike the conventional polishing process, the stripping mechanism of the Lithium niobate thin film is changed by controlling annealing temperature, which can improve the surface morphology of the peeling lithium niobate thin film. We prepared the 128° Y–X POS substrate with high single-crystal Lithium niobate thin film and surface roughness of 3.91 nm through Benzocyclobutene bonding. After simulating the surface acoustic wave (SAW) characteristics of the POS substrate, the results demonstrate that the Benzocyclobutene layer not only performs as a bonding layer but also can couple more vibrations into the LN thin film. The electromechanical coupling coefficient of the POS substrate is up to 7.59% in the Rayleigh mode when hLN/λ is 0.3 and hBCB/λ is 0.1. Therefore, as a high-performance substrate material, the POS substrate has proved to be an efficient method to miniaturize and integrate the SAW sensor.