Plate wave devices with wave confinement structures and fabrication methods
AssigneeQorvo US, Inc.
InventorKushal Bhattacharjee
Life of this patent
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Abstract
A micro-electrical-mechanical system (MEMS) guided wave device includes a single crystal piezoelectric layer and at least one guided wave confinement structure configured to confine a laterally excited wave in the single crystal piezoelectric layer. A bonded interface is provided between the single crystal piezoelectric layer and at least one underlying layer. A multi-frequency device includes first and second groups of electrodes arranged on or in different thickness regions of a single crystal piezoelectric layer, with at least one guided wave confinement structure. Segments of a segmented piezoelectric layer and a segmented layer of electrodes are substantially registered in a device including at least one guided wave confinement structure.
Claims15
A method of fabricating a micro-electrical-mechanical system (MEMS) guided wave device, the method comprising:
- locally thinning a single crystal piezoelectric material layer to define a first thickness region and a second thickness region, wherein a thickness of the first thickness region differs from a thickness of the second thickness region;
- depositing a temperature compensation material on a surface of the first thickness region and on a surface of the second thickness region, wherein the temperature compensation material comprises a first temperature compensation layer thickness proximate to the first thickness region, the temperature compensation material comprises a second temperature compensation layer thickness proximate to the second thickness region, and the second temperature compensation layer thickness differs from the first temperature compensation layer thickness;
- bonding the locally thinned single crystal piezoelectric material layer on or over an underlying layer to provide a bonded interface;
- defining a first plurality of electrodes arranged on or adjacent to the first thickness region and configured for transduction of a lateral acoustic wave having a wavelength 21 in the first thickness region;
- and
- defining a second plurality of electrodes arranged on or adjacent to the second thickness region and configured for transduction of a lateral acoustic wave having a wavelength 22 in the second thickness region.
A method of fabricating a micro-electrical-mechanical system (MEMS) guided wave device, the method comprising:
- locally thinning a single crystal piezoelectric material layer to define a first thickness region and a second thickness region, wherein a thickness of the first thickness region is greater than a thickness of the second thickness region, the single crystal piezoelectric material layer comprises an upper surface and a lower surface that opposes the upper surface, and the local thinning of the single crystal piezoelectric material layer comprises removing material from the lower surface;
- providing a temperature compensation material on a lower surface of the second thickness region, and not on a lower surface of the first thickness region;
- bonding the locally thinned single crystal piezoelectric material layer on or over an underlying layer to provide a bonded interface;
- defining a first plurality of electrodes on the upper surface on or adjacent to the first thickness region and configured for transduction of a lateral acoustic wave having a wavelength λ1 in the first thickness region;
- and
- defining a second plurality of electrodes on the upper surface arranged on or adjacent to the second thickness region and configured for transduction of a lateral acoustic wave having a wavelength λ2 in the second thickness region;
- wherein the first plurality of electrodes is substantially coplanar with the second plurality of electrodes.
Dependencies are inferred from the claim text.