Pyroelectric detection device with stressed suspended membrane

Patent metadata

Field	Value
Publication number	US-11035734-B2
Application number	US-201916514090-A
Country	US
Kind code	B2
Filing date	Jul 17, 2019
Priority date	Jul 18, 2018
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

Pyroelectric detection device, comprising at least:a suspended membrane;a pyroelectric detection element located on the suspended membrane and comprising at least one portion of pyroelectric material located between first and second electrodes, the first electrode being located between said at least one portion of pyroelectric material and the suspended membrane;and in which the membrane and the pyroelectric detection element are subjected to a higher compression stress than a limiting buckling stress of the suspended membrane and the pyroelectric detection element and together form a bistable structure.

First claim

The invention claimed is:

1. Pyroelectric detection device, comprising at least:
a suspended membrane;
a pyroelectric detection element located on the suspended membrane and comprising at least one portion of pyroelectric material located between first and second electrodes, the first electrode being located between said at least one portion of pyroelectric material and the suspended membrane;
and in which the suspended membrane and the pyroelectric detection element are subjected to a higher compression stress than a limiting buckling stress of the suspended membrane and the pyroelectric detection element and together form a bistable structure.

2. The pyroelectric detection device according to claim 1 , wherein the suspended membrane comprises at least one of the following materials: SiO 2 , Si, SiN.

3. The pyroelectric detection device according to claim 1 , also comprising a substrate in which at least one cavity is formed, the suspended membrane comprising edges fixed to the substrate and at least one suspended part located facing said at least one cavity.

4. The pyroelectric detection device according to claim 1 , wherein the pyroelectric detection element comprises a black body comprising at least one of the second electrode and a portion of material absorbing infrared radiation located on the second electrode.

5. The pyroelectric detection device according to claim 4 , wherein the material absorbing infrared radiation comprises at least one of the following materials: TiN, Ni—Cr, Ni, black metal such that platinum black or black gold.

6. The pyroelectric detection device according to claim 1 , wherein the pyroelectric material corresponds to at least one of the following materials: PZT, AlN, KNN, NBT-BT, PMN-PT, LTO, LNO, PVDF.

7. The pyroelectric detection device according to claim 1 , wherein the first electrode comprises platinum.

8. The pyroelectric detection device according to claim 1 , wherein the second electrode comprises at least one of the following materials: Pt, Ru, Ir, TiW, Au, Ni, Ni—Cr, TiN.

9. Method of fabricating a pyroelectric detection device, comprising at least:
fabrication of a suspended membrane;
fabrication of a pyroelectric detection element located on the suspended membrane and comprising at least one portion of pyroelectric material located between first and second electrodes, the first electrode being located between said at least one portion of pyroelectric material and the suspended membrane;
and in which the suspended membrane and the pyroelectric detection element are subjected to a higher compression stress than a limiting buckling stress of the suspended membrane and the pyroelectric detection element and together form a bistable structure.

10. The method according to claim 9 , wherein the suspended membrane is obtained by making at least one layer of material stressed in compression that will form the suspended membrane on a substrate, then after making the pyroelectric detection element on said at least one layer of material, making at least one cavity in the substrate, releasing at least part of the suspended membrane that is suspended facing said at least one cavity.

11. The method according to claim 10 , wherein said at least one layer of material stressed in compression is made by thermal oxidation of the substrate that comprises at least one semiconductor, and/or by deposition of SiO 2 on the substrate.

12. The method according to claim 10 , wherein fabrication of the pyroelectric detection element includes the following steps:
fabrication of at least one first electrode layer on said at least one layer of material stressed in compression;
fabrication of at least one layer of pyroelectric material on said at least one first electrode layer;
fabrication of at least one second electrode layer on said at least one layer of pyroelectric material;
structuring of each of said at least one first electrode layer and said at least one second electrode layer and of said at least one layer of pyroelectric material such that remaining portions of these layers form the pyroelectric detection element.

13. The method according to claim 12 , also comprising a step to deposit at least one layer of material absorbing infrared radiation on said at least one second electrode layer between the step to deposit said at least one second electrode layer and the structuring step, and wherein the structuring step is also carried out for said at least one layer of material absorbing infrared radiation such that a remaining portion of said at least one layer of material absorbing infrared radiation located on the second electrode forms part of a black body of the pyroelectric detection element.

14. The method according to claim 12 , wherein said at least one second electrode layer comprises a thickness and a material such that the second electrode forms part of the black body of the pyroelectric detection element.

Assignees

• Commissariat Energie Atomique

Inventors

• Le Rhun Gwenael
• Fanget Stephane

Classifications

• G01J5/34 Primary

  using capacitors, e.g. pyroelectric capacitors · CPC title

• G01J5/024

  Special manufacturing steps or sacrificial layers or layer structures · CPC title

• G01J5/0225

  Shape of the cavity itself or of elements contained in or suspended over the cavity · CPC title

• G01J2005/0077

  Imaging · CPC title

• G01J5/044

  Environment with strong vibrations or shocks · CPC title