Acoustic wave sensor

Patent metadata

Field	Value
Publication number	US-10684163-B2
Application number	US-201715679162-A
Country	US
Kind code	B2
Filing date	Aug 17, 2017
Priority date	Aug 17, 2016
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

An acoustic wave sensor may include: a continuous membrane deflectable by acoustic waves to be detected, and a piezoelectric layer provided on the membrane and including a plurality of piezoelectric layer portions respectively equipped with at least two individual electric contact structures configured to electrically connect the respective piezoelectric layer portions. Electric contact structures associated with different piezoelectric layer portions may be separated from each other.

First claim

What is claimed is:

1. An acoustic wave sensor, comprising:
a continuous membrane deflectable by acoustic waves to be detected; and
a piezoelectric layer provided on the membrane and comprising a plurality of piezoelectric layer portions respectively equipped with at least two individual electric contact structures configured to electrically connect the respective piezoelectric layer portions, wherein the electric contact structures associated with different piezoelectric layer portions are separated from each other,
wherein the plurality of piezoelectric layer portions comprises an inner piezoelectric layer portion and an outer piezoelectric layer portion, wherein the outer piezoelectric layer portion is positioned closer to an outer periphery of the membrane than the inner piezoelectric layer portion, and
wherein the inner and outer piezoelectric layer portions each comprise a plurality of piezoelectric layer portion segments consecutively arranged in a circumferential direction of the membrane,
wherein the electric contact structures associated with each of the piezoelectric layer portions comprising a top electrode and a bottom electrode associated with the piezoelectric layer portion for electrically connecting the piezoelectric layer portion,
wherein the top and bottom electrodes comprise top and bottom electrode segments respectively associated with the piezoelectric layer portion segments, wherein the piezoelectric layer portion segments are respectively interposed between the respective top electrode segment and the bottom electrode segment in a direction parallel to the thickness direction of the membrane, and wherein for each piezoelectric layer portion segment, sidewalls of the top electrode segment, the bottom electrode segment and the piezoelectric layer are coplanar.

2. The acoustic wave sensor of claim 1 ,
wherein at least one or both of the inner and outer piezoelectric layer portions have a rotationally symmetric shape.

3. The acoustic wave sensor of claim 1 ,
wherein at least one or both of the inner and outer piezoelectric layer portions have an annular shape.

4. The acoustic wave sensor of claim 1 ,
wherein at least two of the piezoelectric layer portions are electrically connected in series; and/or
wherein at least two or all of the plurality of piezoelectric layer portion segments are electrically connected in series.

5. The acoustic wave sensor of claim 1 ,
wherein the bottom electrode segment of a piezoelectric layer portion segment arranged between two immediately adjacent piezoelectric layer portion segments in the circumferential direction of the membrane is electrically connected to a top electrode segment of one of the adjacent piezoelectric layer portion segments, and the top electrode segment of the piezoelectric layer portion segment is electrically connected to a bottom electrode segment of the respective other one of the adjacent piezoelectric layer portion segments.

6. The acoustic wave sensor of claim 5 , further comprising:
a holder supporting the membrane.

7. The acoustic wave sensor of claim 6 ,
wherein the holder protrudes beyond a surface of the membrane opposite to the piezoelectric layer.

8. The acoustic wave sensor of claim 7 ,
wherein the holder is in physical contact with a sidewall at an outer periphery of the membrane.

9. The acoustic wave sensor of claim 8 ,
wherein the holder has a substantially annular segment shape or a substantially annular shape.

10. The acoustic wave sensor of claim 1 ,
wherein the membrane has a diameter in a range of about 500 to about 2000 μm; and/or
wherein the membrane has a thickness in a range of about 100 to about 1000 nm.

11. The acoustic wave sensor of claim 1 ,
wherein the piezoelectric layer has a thickness in a range of about 100 to about 500 nm.

12. The acoustic wave sensor of claim 1 ,
wherein at least one of the electrodes or all the electrodes has/have a thickness in a range of about 100 to about 300 nm.

13. A method of manufacturing an acoustic wave sensor, the method comprising:
forming a piezoelectric layer of a piezoelectric material on a continuous membrane; and
forming a plurality of electric contact structures in physical contact with a plurality of piezoelectric layer portions for electrically connecting the respective piezoelectric layer portions, wherein each piezoelectric layer portion is equipped with at least two electric contact structures and wherein the electric contact structures associated with different piezoelectric layer portions are separated from each other,
wherein the forming the piezoelectric layer comprises forming the piezoelectric layer with a plurality of piezoelectric layer portions comprising an inner piezoelectric layer portion and an outer piezoelectric layer portion, wherein the outer piezoelectric layer portion is positioned closer to an outer periphery of the membrane than the inner piezoelectric layer portion,
wherein the forming the piezoelectric layer comprises forming the piezoelectric layer with a plurality of piezoelectric layer portions so that the inner piezoelectric layer portion and the outer piezoelectric layer portion each comprises a plurality of piezoelectric layer portion segments consecutively arranged in a circumferential direction of the membrane,
wherein the forming the electric contact structures comprises respectively forming a top electrode and a bottom electrode for each piezoelectric layer portion for electrically connecting the piezoelectric layer portions, wherein each bottom electrode is formed above the membrane so as to be interposed between the membrane and the piezoelectric layer portion in a direction parallel to a thickness direction of the membrane and wherein each piezoelectric layer portion is interposed between the respective bottom electrode and the top electrode in the direction parallel to the thickness direction of the membrane so that sidewalls of the piezoelectric layer portion and sidewalls of the top and bottom electrode are coplanar.

14. The method of claim 13 , further comprising:
electrically connecting in series at least two or all of the piezoelectric layer portions; and/or
electrically connecting in series at least two or all of the plurality of piezoelectric layer portion segments of a piezoelectric layer portion.

15. The method of claim 13 , further comprising:
forming a holder supporting the membrane;
wherein the holder is formed to physically contact an outer periphery of the membrane.

16. A device for detecting acoustic waves comprising an acoustic wave sensor, wherein the acoustic wave sensor comprises
a continuous membrane deflectable by acoustic waves to be detected; and
a piezoelectric layer provided on the membrane and comprising a plurality of piezoelectric layer portions respectively equipped with at least two individual electric contact structures configured to electrically connect the respective piezoelectric layer portions, wherein the electric contact structures associated with different piezoelectric layer portions are separated from each other,
wherein the plurality of piezoelectric layer portions comprises an inner piezoelectric layer portion and an outer piezoelectric layer portion, wherein the outer piezoelectric layer portion is positioned closer to an outer periphery of the membrane than the inner piezoelectric layer portion,
wherein the forming the piezoelectric layer comprises forming the piezoelectric layer with a plurality of piezoelectric layer portions so that the inner piezoelectric layer portion and the outer piezoelectric layer portion each comp

Assignees

• Infineon Technologies Ag

Inventors

• Dehe Alfons
• Dorfmeister Manuel
• Schmid Ulrich
• Schneider Michael

Classifications

• H04R17/025

  using a piezoelectric polymer · CPC title

• H04R31/00

  Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor {(manufacture of microstructural arrangements of deformable or non-deformable structures in general B81C1/00182)} · CPC title

• H10N30/506

  having a cylindrical shape and having stacking in the radial direction, e.g. coaxial or spiral type rolls · CPC title

• G01H11/08 Primary

  using piezoelectric devices · CPC title

• H01L41/0836

  Electricity · mapped topic