Surface acoustic wave resonator and manufacturing method therefor
View Patent ↗A surface acoustic wave resonator and a manufacturing method thereof are provided. The surface acoustic wave resonator includes a piezoelectric substrate, an interdigital transducer located on a surface of the piezoelectric substrate, and a suppression layer for suppressing a transverse mode arranged on at least one of the piezoelectric substrate and the interdigital transducer.
1 . A surface acoustic wave resonator, comprising a piezoelectric substrate, an interdigital transducer and a suppression layer for suppressing a transverse mode, wherein the interdigital transducer is arranged on a surface of the piezoelectric substrate, and the suppression layer is arranged on at least one of the piezoelectric substrate and the interdigital transducer,
wherein the interdigital transducer has a central area, first and second non-central areas and first and second bus areas, the first and second bus areas are located on both outer sides of the central area in a transverse direction, respectively, the first non-central area is located between the central area and the first bus area in the transverse direction, the second non-central area is located between the central area and the second bus area in the transverse direction, the suppression layer comprises a two first temperature compensation layers and a second temperature compensation layer, a sound velocity in each of the two first temperature compensation layers is lower than a sound velocity in the second temperature compensation layer, one of the two first temperature compensation layers covers at least a part of the first non-central area, the other of the two first temperature compensation layers covers at least a part of the second non-central area, and the second temperature compensation layer covers a part of the interdigital transducer located on an outer side of each of the two first temperature compensation layers in the transverse direction and a part of the interdigital transducer located between the two first temperature compensation layers in the transverse direction; and
wherein the second temperature compensation layer comprises an outer compensation layer and an inner compensation layer with different sound velocities, the outer compensation layer is located on the outer side of each of the two first temperature compensation layers, and the inner compensation layer is located between the two first temperature compensation layers.
2 . A method for manufacturing a surface acoustic wave resonator, comprising:
providing a piezoelectric substrate;
fabricating an interdigital transducer on the piezoelectric substrate; and
forming a suppression layer for suppressing a transverse mode on at least one of the piezoelectric substrate and the interdigital transducer,
wherein the interdigital transducer has a central area, first and second non-central areas and first and second bus areas, the first and second bus areas are located on both outer sides of the central area in a transverse direction, respectively, the first non-central area is located between the central area and the first bus area in the transverse direction, and the second non-central area is located between the central area and the second bus area in the transverse direction,
wherein forming the suppression layer for suppressing the transverse mode comprises:
forming a two first temperature compensation layers and a second temperature compensation layer, wherein one of the two first temperature compensation layers covers at least a part of the first non-central area, the other of the two first temperature compensation layers covers at least a part of the second non-central area, and the second temperature compensation layer covers a part of the interdigital transducer located on an outer side each of the two first temperature compensation layers in the transverse direction and a part of the interdigital transducer located between the two first temperature compensation layers in the transverse direction; and
wherein a sound velocity in each of the two first temperature compensation layers is lower than a sound velocity in the second temperature compensation layer, the second temperature compensation layer comprises an outer compensation layer located on the outer side of each of the two first temperature compensation layers and an inner compensation layer located between the two first temperature compensation layers, and a sound velocity in the inner compensation layer is different from a sound velocity in the outer compensation layer.