Temperature compensated saw with high quality factor

Abbott, Ben; Chen, Alan; Daniel, Tim; Gamble, Kevin J.; Kook, T.; Solal, M.; Steiner, K. G.; Aigner, Robert; Malocha, Svetlana; Hella, Curtis; Gallagher, M.; Kuypers, Jan H.

doi:10.1109/ultsym.2017.8092294

Cited by 16 publications

(5 citation statements)

References 14 publications

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“…The former feature is common to devices in which the resonator is coated by different layers. In filters dense metal electrodes are used (Cu) to oppose this phenomenon [33]. In high-temperature sensors, electrodes based on Pt and Ir are often the only choice [34] and can efficiently fit the purpose.…”

Section: Room Temperature Resultsmentioning

confidence: 99%

AlN/GaN/Sapphire heterostructure for high-temperature packageless acoustic wave devices

Bartoli

Aubert

Moutaouekkil

et al. 2018

Sensors and Actuators A: Physical

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Surface acoustic waves (SAW) technology is very promising to achieve wireless sensors able to operate in high temperature environments up to possibly 1000°C. However, there is currently a bottleneck related to the packaging of such sensors. The current high-temperature packaging solutions can withstand 600°C at most. This limitation could be overtaken by the development of packageless devices, based on the waveguiding layer acoustic waves (WLAW) principle. In such devices, the acoustic wave is confined inside an inner layer and is then isolated from undesired surface perturbations like dust deposition. In this paper, we investigate the performance of an AlN/IDT/GaN/Sapphire WLAW device used as a temperature sensor able to operate up to 500°C. After validating a room-temperature GaN material constant set with basic SAW measurements performed on IDT/GaN/Sapphire structure, the AlN/IDT/GaN/Sapphire device is simulated to determine the optimal relative thicknesses of AlN and GaN films in order to obtain a good wave confinement. Based on these calculations, an experimental WLAW device is performed and electrically characterized. The full wave confinement is experimentally confirmed by the lamination of an acoustic absorber on top of the device: no change in the scattering parameters was observed. The WLAW device is then electrically characterized between the ambient temperature and 500°C. A temperature coefficient of frequency (TCF) value of-34.6 ppm/°C is obtained, demonstrating the potential of the WLAW AlN/IDT/GaN/Sapphire structure as a packageless temperature sensor. Finally, the theoretical TCF of the AlN/IDT/GaN/Sapphire structure was numerically calculated by changing the material constants of AlN, GaN and Sapphire according to the temperature coefficients available in the literature. The theoretical and experimental data were found in good accordance.

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Section: Room Temperature Resultsmentioning

confidence: 99%

AlN/GaN/Sapphire heterostructure for high-temperature packageless acoustic wave devices

Bartoli

Aubert

Moutaouekkil

et al. 2018

Sensors and Actuators A: Physical

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“…However, since the amorphous SiO 2 is non-piezoelectric [ 31 ], the infiltration will also lead to a decrease in the electromechanical coupling coefficient of the propagating SAW, and the deposition of SiO 2 will also affect the reflection characteristics of the surface acoustic wave. The other is a lithium tantalate (LT) structure on sapphire/Si/other materials [ 32 ], Sapphire itself has good temperature compensation and a large Young’s modulus. It is very difficult to manufacture and requires careful control of electrode thickness and oxide film thickness.…”

Section: Saw Filter Technologymentioning

confidence: 99%

Development and Application of SAW Filter

Chen

Zhu

2022

Micromachines

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With the in-depth advancement of the fifth generation (5G) mobile communication technology, the technical requirements for filters are also constantly improving. Surface acoustic wave (SAW) filters are widely used in home TV, mobile communications, radio frequency filters and radar due to their simple structure, few mask layers, easy miniaturization, and low cost. Through the continuous improvement of communication technology, SAW has developed into various high-performance acoustic filters from bulk SAW with the support of some new architectures, new materials and advanced modeling techniques. This paper analyzes and reviews the research situation of SAW filter technology.

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“…By carefully designing the metal ratio DF h in corresponds to the slower border region phase velocity (v b ) together with the border width w b , the relative coupling coefficients of transverse modes are reduced to a negligible level and amplitudes of the transverse modes in the type I S 0 are effectively reduced, or even eliminated in electrical response. In addition, the Q of the main mode is also improved by the reduction of transverse leakage, which is one of the main steps to achieve a high-Q resonator [30].…”

Section: B Fem Demonstrationmentioning

confidence: 99%

Transverse Spurious Mode Compensation for AlN Lamb Wave Resonators

2019

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Lamb wave modes with type I dispersion characteristics exhibit strong affinity toward multi transverse modes behavior above resonance frequency (f r) in the AlN Lamb wave resonators (LWRs), especially the high-transduction-efficiency modes: S 0 and S 1 mode. For conventional interdigital transducer (IDT) design, the IDT aperture and IDT gap are the two main factors impacting the transverse mode placements and strengths, according to the wave vector analysis and finite element method (FEM) simulation. Moreover, the convex slowness curve of the Lamb wave modes propagating in AlN platelets allows the waveguiding and weak lateral leakage into busbars by the high-velocity IDT gap region. Apodization, the standard technique to suppress the transverse modes for IDT-excited resonators, suffers from drawbacks, such as additional loss and reduction of the effective coupling coefficient (k 2 eff). Type I Lamb wave modes in AlN show positive slope in the dispersion branch so that a border region of lower Eigen-resonance frequency is required to form piston mode structure for transverse spurious mode suppression and lateral leakage reduction. Based on dispersion calculations and 2.5D FEM simulations, we demonstrate that by designing the low-velocity border region, such as simply changing the IDT layout, the guiding can be improved and a piston mode can be obtained for the type I Lamb wave modes. INDEX TERMS Aluminum nitride, dispersion, lamb wave, S 0 mode, S 1 mode, transverse modes, piston mode structure.

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Temperature compensated saw with high quality factor

Cited by 16 publications

References 14 publications

AlN/GaN/Sapphire heterostructure for high-temperature packageless acoustic wave devices

AlN/GaN/Sapphire heterostructure for high-temperature packageless acoustic wave devices

Development and Application of SAW Filter

Transverse Spurious Mode Compensation for AlN Lamb Wave Resonators

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