US 12,255,612 B2
Surface acoustic wave device on composite substrate
Sylvain Ballandras, Besançon (FR); and Thierry LaRoche, Besançon (FR)
Assigned to Soitec, Bernin (FR)
Filed by Soitec, Bernin (FR)
Filed on Feb. 21, 2024, as Appl. No. 18/583,235.
Application 18/583,235 is a continuation of application No. 17/043,559, granted, now 11,936,364, previously published as PCT/EP2019/056436, filed on Mar. 14, 2019.
Claims priority of application No. 1852750 (FR), filed on Mar. 29, 2018.
Prior Publication US 2024/0250659 A1, Jul. 25, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H03H 9/02 (2006.01); H03H 3/08 (2006.01); H03H 9/145 (2006.01); H03H 9/25 (2006.01); H03H 9/64 (2006.01)
CPC H03H 9/02866 (2013.01) [H03H 3/08 (2013.01); H03H 9/02574 (2013.01); H03H 9/02661 (2013.01); H03H 9/145 (2013.01); H03H 9/25 (2013.01); H03H 9/6489 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A surface acoustic wave device, comprising:
a base substrate;
a piezoelectric layer;
an electrode layer in between the piezoelectric layer and the base substrate; and
a comb electrode formed on the piezoelectric layer comprising a plurality of electrode fingers with a pitch ρ, defined as ρ=λ, with λ being a wavelength of a standing acoustic wave generated by applying opposite potentials to the electrode layer and the comb electrode,
wherein, the piezoelectric layer comprises at least one region located in between the plurality of electrode fingers in which at least one physical parameter is different compared to the region underneath the plurality of electrode fingers; and
wherein either a) a thickness t of the piezoelectric layer is defined by optimization of a coupling between a bulk acoustic wave and the standing acoustic wave generated between the comb electrode and the electrode layer and is on the order or smaller than the wavelength λ of the standing acoustic wave or b) a dimension of the comb electrode is defined by optimization of the coupling between the bulk acoustic wave and the standing acoustic wave generated by the comb electrode.