Conference Paper

Transformation of surface acoustic waves into boundary waves in Piezoelectric/Metal/Dielectric structures

DOI: 10.1109/ULTSYM.2009.5441706 Conference: Ultrasonics Symposium (IUS), 2009 IEEE International
Source: IEEE Xplore

ABSTRACT A universal technique was developed for analysis of SAW and boundary waves (BW) in Piezoelectric/Metal/Dielectric structures with uniform metal film sandwiched between piezoelectric substrate and dielectric overlay, and dielectric overlay thickness varying between zero and infinite value. This technique was applied to 128°YX LN with Cu and silica glass films. For each mode propagating in this structure, continuous transformation of the wave polarization and distribution of its energy along the vertical axis were analyzed as functions of metal and dielectric film thickness. The found dependences reveal the mechanisms of wave transformation from SAW to BW.

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Available from: Natalya F. Naumenko, Jul 30, 2015
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    • "II. METHOD " SDA-FEM-SDA " The approach, which was previously developed for analysis of acoustic modes in multi-layered structures with uniform metal film at the interface [3], has been extended to metal gratings sandwiched between two generally multi-layered half-spaces. The analyzed structure is schematically shown in Fig.1. "
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    ABSTRACT: A numerical technique, which combines FEM analysis of electrode area with matrix formalism applied to spectral domain analysis (SDA) of eigen modes in multi-layered substrate and multi-layered dielectric upper half-space, is described as an efficient tool of investigating the wave characteristics in periodic metal grating sandwiched between two multi-layered half-spaces, with arbitrary thickness of each layer. The universal character of the developed technique is illustrated by few examples of its application to different types of structure providing propagation of common SAW, boundary waves at interface, plate modes, normal modes in a thin film deposited over the grating etc. The transformation between the waves with continuously increasing film thicknesses can be observed.
    Ultrasonics Symposium (IUS), 2010 IEEE; 01/2010
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    • "To some extent, such behavior agrees with previously observed behavior of SAW modes in uniform Cu film sandwiched between 128ºYX LN and SiO 2 [1]. The only one boundary wave having nonzero k 2 is SH-polarized in both cases. "
    IEEE Ultrasonics Symposium; 01/2010
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    ABSTRACT: The mechanism of SAW transformation with variation of film thickness is investigated in Piezoelectric/Metal grating/Dielectric structures via simulation of acoustic fields. By way of example, YX and 128°YX cuts of lithium niobate are considered as substrates, with Cu grating and isotropic SiO2 as overlay. The motions, which accompany the wave propagation in the sagittal plane, are visualized, and the added contour plots show variation of shear-horizontal displacements. The transformation of the wave nature with SiO2 thickness increasing from zero to few periods is observed for each wave propagating in the analyzed material structures. Examples of wave transformation into boundary waves and into normal modes propagating in SiO2 film are demonstrated. The difference in the behavior of SAW modes in the grating is correlated with velocity versus film thickness dependences.
    Ultrasonics Symposium (IUS), 2010 IEEE; 01/2010