Pseudo and High Velocity Pseudo SAWs

Cunha, M. Pereira da

doi:10.1016/s0129-1564(00)00071-4

Cited by 8 publications

(3 citation statements)

References 24 publications

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“…References [33][34][35] provide a very useful list of substrates types and crystallographic orientations along which low-attenuated, strongly-coupled PSAW and HVPSAW travel (such as 64°YX LiNbO 3 , 36°YX LiTaO 3 , quartz ST-X, LiNbO 3 with Euler angles (90° 90° 36°), (90° 90° 31°) LiTaO 3 , and (0° 45° 90°) Li 2 B 4 O 7 ). For sake of completeness, the same references list other information that are fundamental for the design of the device parameters (operating frequency, IDTs centre-to-centre distance, number of IDTs finger pairs, IDTs aperture, etc.)…”

Section: Pseudo Saw and High Velocity Psaw Sensorsmentioning

confidence: 99%

Guided acoustic wave sensors for liquid environments

Caliendo

Hamidullah

2019

J. Phys. D: Appl. Phys.

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Surface acoustic wave (SAW) based sensors for applications to gaseous environments have been widely investigated since the last 1970s. More recently, the SAW-based sensors focus has shifted towards liquid-phase sensing applications: the SAW sensor contacts directly the solution to be tested and can be utilized for characterizing physical and chemical properties of liquids, as well as for biochemical sensor applications. The design of liquid phase sensors requires the selection of several parameters, such as the acoustic wave polarizations (i.e., elliptical, longitudinal and shear horizontal), the wave-guiding medium composition (i.e., homogeneous or non-homogeneous half-spaces, finite thickness plates or composite suspended membranes), the substrate material type and its crystallographic orientation. The paper provides an overview of different types of SAW sensors suitable for application to liquid environments, and intents to direct the attention of the designers to combinations of materials, waves nature and electrode structures that affect the sensor performances. ORCID iDsC Caliendo https://orcid.org/0000-0002-8363-2972 M Hamidullah https://orcid.org/0000-0003-2131-4335

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Section: Pseudo Saw and High Velocity Psaw Sensorsmentioning

confidence: 99%

Guided acoustic wave sensors for liquid environments

Caliendo

Hamidullah

2019

J. Phys. D: Appl. Phys.

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“…This cut allows the propagation of a leaky wave, which presents advantages such as: higher electromechanical coupling coefficient (K 2 = 0.047) and a moderate temperature coefficient of delay (TCD) over other SAW counterparts 17 . The fabricated device's structure parameters and deposition conditions of the of the PECVD SiN x are described in 16 and the deposition conditions for the r.f.…”

Section: Fabricationmentioning

confidence: 99%

Comparative study of surface acoustic wave based hydrogen sensors with: InO x /SiN x /36° YX LiTaO 3 structure

Fechete

Włodarski

Kalantar‐zadeh

et al. 2005

Microelectronics: Design, Technology, and Packaging II

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Layered Surface Acoustic Wave (SAW) based sensors with: InO x / SiN x / 36 o YX LiTaO 3 structure were developed for sensing different hydrogen (H 2 ) concentrations between 0.06% (600ppm) and 1% H 2 in synthetic air. This paper presents a comparative study of the sensors performances in terms of response time, recovery time and response magnitude as a function of operational temperature. The SAW devices consist of metal interdigitated electrodes fabricated on lithium tantalate (LiTaO 3 ) piezoelectric substrate forming the input and output Interdigital Transducers (IDTs). A 1 µm thick silicon nitride (SiN x ) intermediate layer was deposited over these finger pairs, either by Plasma Enhanced Chemical Vapour Deposition (PECVD) or by r.f. magnetron sputtering. A 100 nm thin film of indium oxide (InO x ) deposited by r.f. magnetron sputtering provides the selectivity towards hydrogen. The highest sensitivity for the sensor with r.f. magnetron sputtered SiN x intermediate layer was recorded at 190° C, when the frequency shift of 361 KHz for 1% H 2 in synthetic air was recorded. However larger responses were obtained for the sensor with the PECVD SiN x intermediate layer at 290° C, when the large frequency shift of 516 KHz was recorded for the same H 2 concentration. Microstructural characterization of the InO x and SiN x films by Atomic Force Microscopy (AFM) and XRay Photoelectron Spectroscopy (XPS) is also presented.

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“…It should also be said that the problem to be studied is directly related to the properties of high-velocity leaky and surface waves near the quasi-transverse and quasi-longitudinal branches that have been intensively studied numerically during recent years (e.g. da Cunha & Adler 1995;da Cunha 2001;Biryukov & Weihnacht 1998;Naumenko 1994;Sato & Abe 1998;Tonami et al . 1995).…”

Section: Introductionmentioning

confidence: 99%

Quasi–bulk surface and leaky waves in piezoelectrics of unrestricted symmetry

Darinskii

Weihnacht

2003

Proc. R. Soc. Lond. A

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A theoretical study has been made of the effect of piezoelectric coupling on exceptional bulk waves (EBWs) that exist on the surface of a medium if the piezomoduli are made equal to zero. The analysis has been carried out assuming that the medium is of generic symmetry and that the piezoeffect is weak. In combination with elastic anisotropy, the piezoelectric coupling can cause the appearance of surface and leaky acoustic waves (SAWs and LSAWs) at orientations close to those supporting EBWs. The existence conditions for SAWs and LSAWs have been studied. In particular, it has been shown that the piezoeffect provides the existence of non-attenuating fast SAWs near the EBW associated with the branch of fast quasi-transverse bulk waves. Such an SAW appears independently of the crystallographic symmetry and material constants if the surface of the substrate is metallized. On the non-metallized surface, it may or may not exist, depending on the material constants. In addition, contrary to the case of non-piezoelectric media, quasi-longitudinal EBWs generally give rise to the leaky waves. Numerical computations for SiO 2 crystal confirm our analytic estimations.

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Pseudo and High Velocity Pseudo SAWs

Cited by 8 publications

References 24 publications

Guided acoustic wave sensors for liquid environments

Guided acoustic wave sensors for liquid environments

Comparative study of surface acoustic wave based hydrogen sensors with: InO x /SiN x /36° YX LiTaO 3 structure

Quasi–bulk surface and leaky waves in piezoelectrics of unrestricted symmetry

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