Guided wave devices with selectively thinned piezoelectric layers
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 plurality of electrodes arranged below a piezoelectric layer (e.g., either embedded in a slow wave propagation layer or supported by a suspended portion of the piezoelectric layer) and configured for transduction of a lateral acoustic wave in the piezoelectric layer. The piezoelectric layer permits one or more additions or modifications to be made thereto, such as trimming (thinning) of selective areas, addition of loading materials, sandwiching of piezoelectric layer regions between electrodes to yield capacitive elements or non-linear elastic convolvers, addition of sensing materials, and addition of functional layers providing mixed domain signal processing utility.
Claims21
A micro-electrical-mechanical system (MEMS) guided wave device comprising:
- a piezoelectric layer;
- a plurality of electrodes arranged in a slow wave propagation layer disposed below the piezoelectric layer and configured for transduction of a lateral acoustic wave in the piezoelectric layer;
- and
- a guided wave confinement structure arranged proximate to the slow wave propagation layer and configured to confine the lateral acoustic wave in the piezoelectric layer and the slow wave propagation layer;
- wherein the piezoelectric layer comprises a first thickness region and a second thickness region, and a thickness of the first thickness region differs from a thickness of the second thickness region.
A method of fabricating a MEMS guided wave device, the method comprising:
- defining a plurality of electrodes on a piezoelectric layer;
- depositing a slow wave propagation layer over the plurality of electrodes and at least a portion of the piezoelectric layer to cause the plurality of electrodes to be arranged in the slow wave propagation layer, with the slow wave propagation layer disposed below the piezoelectric layer;
- providing a guided wave confinement structure proximate to the slow wave propagation layer, wherein the guided wave confinement structure is configured to confine a lateral acoustic wave in the piezoelectric layer and the slow wave propagation layer;
- and
- locally thinning the piezoelectric 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;
- wherein the plurality of electrodes is configured for transduction of a lateral acoustic wave in the piezoelectric layer.
A method of fabricating a MEMS guided wave device, the method comprising:
- defining a plurality of electrodes in a slow wave propagation layer;
- bonding or depositing a piezoelectric layer on or over the slow wave propagation layer;
- and
- locally thinning the piezoelectric 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.
Dependencies are inferred from the claim text.