Title :
A full-wave analysis of surface acoustic waves propagating on a SiO2 overlay/metal grating/rotated YX-LiNbO3 substrate structure
Author :
Wang, Yiliu ; Hashimoto, Ken-Ya ; Omori, Tatsuya ; Yamaguchi, Masatsune
Author_Institution :
Grad. Sch. of Eng., Chiba Univ., Chiba
Abstract :
This paper describes full-wave analysis of the SiO2 overlay with finite thickness/metal grating/rotated YX-LN substrate structure. The influence of thickness and surface topology of the SiO2 overlay, metal grating selection (copper or aluminum) upon excitation and propagation characteristics of acoustic guided modes are discussed in detail. It is shown that in the structure there propagate several types of acoustic guided modes. One type of mode concentrates the energy near the metal grating, and becomes the piezoelectric boundary acoustic waves with relatively large electromechanical coupling when SiO2 thickness becomes semi-infinite. Another mode concentrates its energy near the top surface of the SiO2 overlay and becomes the Rayleigh-type SAW on SiO2 when thickness is semi-infinite. With an increase in SiO2 thickness, it rapidly loses its piezoelectric coupling. The remaining mode is a series of guided modes bounded in the SiO2 layer, in which the SiO2 layer behaves as a waveguide because of its low acoustic wave velocities.
Keywords :
Rayleigh waves; acoustic wave propagation; aluminium; copper; electrodes; electromechanical effects; lithium compounds; piezoelectric materials; silicon compounds; surface acoustic wave devices; surface acoustic waves; surface topography; LiNbO3; Rayleigh-type SAW; SiO2-Al-LiNbO3; SiO2-Cu-LiNbO3; acoustic guided modes; electromechanical coupling; metal grating electrode; piezoelectric boundary acoustic waves; rotated YX- lithium niobate substrate structure; silicon dioxide overlay; surface acoustic waves propagation; surface topology; Acoustic propagation; Acoustic waves; Electrodes; Filters; Gratings; Packaging; Substrates; Surface acoustic wave devices; Surface acoustic waves; Topology; PBAW; SH-type; modes; non-leaky;
Conference_Titel :
Ultrasonics Symposium, 2008. IUS 2008. IEEE
Conference_Location :
Beijing
Print_ISBN :
978-1-4244-2428-3
Electronic_ISBN :
978-1-4244-2480-1
DOI :
10.1109/ULTSYM.2008.0292
