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US 2021/0367577 A1Published application
Micro-acoustic device with reflective phononic crystal and method of manufacture
AssigneeRf360 Europe GmbH
InventorsWilli AIGNER, Edgar SCHMIDHAMMER, Maximilian SCHIEK
Life of this patent
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Abstract
A micro-acoustic device comprises a confinement structure (CS) adapted to block propagation of acoustic waves of an acoustic wave resonator (TEL, PL, BEL; ES) at an operation frequency of the device to confine the acoustic waves to the acoustic path or the acoustic volume. It is proposed to use a phononic crystal material for producing the confinement structure.
Claims12
A micro-acoustic device comprising:
- a substrate (SU);
- a piezoelectric layer (PL) on a top surface of the substrate;
- an electrode structure on the piezoelectric layer for exciting acoustic waves at an operation frequency propagating along an acoustic path or within an active volume of the piezoelectric layer;
- and
- a confinement structure (CS) adapted to block propagation of acoustic waves at the operation frequency to confine the acoustic waves to the acoustic path or the acoustic volume, the confinement structure being arranged:
- at a position lateral to the acoustic path;
- and/or
- between substrate and piezoelectric layer;
- and/or
- on the top surface of the electrode structure or the piezoelectric layer.
7 more elements
A method of manufacturing a micro-acoustic device, comprising:
- on a substrate, forming a piezoelectric layer and an electrode structure of the micro-acoustic device adapted to excite acoustic waves at an operation frequency in an acoustic path or an active volume;
- and
- forming a confinement structure in the form of a phononic crystal material to block propagation of acoustic waves at the operation frequency to confine the acoustic waves to the acoustic path or the active volume;
- wherein forming the confinement structure of phononic crystal material comprises:
- a) applying a first layer of repeating units of a first solid material according to a periodic grid onto the substrate or any other device structure already formed on the substrate;
- b) filling gaps between the repeating units with a liquid material;
- c) transforming the liquid material into a solid second material by hardening or solidifying the liquid material to achieve repeating units of second material;
- and
- d) optionally planarizing and structuring the layer to yield a solid and plane layer of repeating units of alternating first and second material.
6 more elements
A method of manufacturing the micro-acoustic device, comprising:
- on a substrate, forming a piezoelectric layer and an electrode structure of the micro-acoustic device adapted to excite acoustic waves at an operation frequency in an acoustic path or an active volume;
- and
- forming a confinement structure in the form of a phononic crystal material to block propagation of acoustic waves at the operation frequency to confine the acoustic waves to the acoustic path or the active volume by printing a three-dimensional periodic pattern with 3D printing technique, the pattern comprising repeating units of a first solid material embedded in a second solid material.
A method of manufacturing a micro-acoustic device comprising:
- on a substrate, forming a piezoelectric layer and an electrode structure of the micro-acoustic device adapted to excite acoustic waves at an operation frequency in an acoustic path or an active volume;
- and
- forming a confinement structure in the form of a phononic crystal material to block propagation of acoustic waves at the operation frequency to confine the acoustic waves to the acoustic path or the active volume,
- wherein forming the confinement structure comprises:
- depositing monodisperse spherical microbeads are on the substrate in a self-assembling process;
- filling the gaps between the microbeads with a liquid polymer material;
- hardening the liquid polymer to transform it into a solid second material thereby yielding a layer of a 2D phononic crystal;
- optionally planarizing and structuring the layer to yield a solid and plane layer of repeating units of alternating first and second material;
- and
- optionally repeating the above steps to form at least one further layer of a 2D phononic crystal wherein the repeating units in the second layer and optionally further layers are respectively offset to the layer below.
7 more elements
Dependencies are inferred from the claim text.