Process for producing a microbolometer comprising a vanadium-oxide-based sensitive material

Patent metadata

Field	Value
Publication number	US-12066332-B2
Application number	US-202017629995-A
Country	US
Kind code	B2
Filing date	Jul 27, 2020
Priority date	Jul 30, 2019
Publication date	Aug 20, 2024
Grant date	Aug 20, 2024

Abstract

A process for producing a microbolometer including a vanadium-oxide-based sensitive material containing an additional chemical element chosen from arsenic, germanium, silicon and phosphorus, the process including: determining an effective amount of the additional chemical element from which the modified compound, having undergone a step of exposure to a temperature T r for a time Δt r , exhibits an electrical resistivity ρ a|r at room temperature that is higher than 10% of its native value; producing the sensitive material in a thin layer, this material being formed from the modified compound having an amount of the additional chemical element that is greater than or equal to the effective amount; and exposing the sensitive material to the temperature T r for the time Δt r .

First claim

The invention claimed is:

1. A process for manufacturing at least one microbolometer, the process comprising:
producing a sensitive material in a thin layer, the sensitive material comprising a first compound comprising vanadium oxide and an additional chemical element, added to the first compound, the additional chemical element comprises arsenic, germanium, silicon, and/or phosphorus, and the additional chemical element comprising no nitrogen;
exposing the sensitive material to a temperature T r greater than ambient temperature for a duration Δt r , performed after the producing, the temperature T r and the duration Δt r being such that the first compound, being amorphous and having a native electrical resistivity value at ambient temperature in a range of from 1 to 30 Ω·cm, having undergone exposure to the temperature T r for the duration Δt r , has an electrical resistivity at ambient temperature less than or equal to 10% of its native value;
determining a non-zero amount of the additional chemical element, referred to as an effective amount, added to the first compound, thus forming a modified compound, starting from which the modified compound, having undergone exposure to the temperature T r for the duration Δt r , has an electrical resistivity Par at ambient temperature greater than 10% of its native value ρ a ;
wherein the producing comprises forming the thin layer of the modified compound having an amount of the additional chemical element(s) greater than or equal to the effective amount determined beforehand, the sensitive material being amorphous, having a native electrical resistivity value Pa at ambient temperature in a range of from 0.1 to 30 Ω·cm, and a homogeneous chemical composition;
such that, following the exposing, the sensitive material then has a noise whose degradation has been limited,
wherein the microbolometer comprises the sensitive material,
wherein the process allows noise degradation associated with the sensitive material to be limited.

2. The process of claim 1 , wherein the additional chemical element is selected from the group consisting of arsenic, germanium, and silicon.

3. The process of claim 1 , wherein the exposing comprises depositing a protective layer, covering the sensitive material.

4. The process of claim 1 , wherein the exposing comprises depositing an encapsulation layer, transparent to the electromagnetic radiation, to be detected and intended to define a cavity in which the microbolometer is located.

5. The process of claim 1 , wherein the temperature T r is at least 330° C.

6. The process of claim 1 , wherein the duration Δt r is at least 90 min.

7. The process of claim 1 , wherein the sensitive material is produced at a temperature less than the temperature T r .

8. The process of claim 1 , the additional chemical element comprises arsenic.

9. The process of claim 1 , the additional chemical element comprises germanium.

10. The process of claim 1 , the additional chemical element comprises silicon.

11. The process of claim 1 , wherein the temperature T r is in a range of from 345° C. to 355° C.

12. The process of claim 1 , wherein the additional chemical element is selected from the group consisting of arsenic, germanium, and silicon, and
wherein the exposing comprises depositing a protective layer, covering the sensitive material.

13. The process of claim 1 , wherein the additional chemical element is selected from the group consisting of arsenic, germanium, and silicon, and
wherein the exposing comprises depositing an encapsulation layer, transparent to the electromagnetic radiation, to be detected and intended to define a cavity in which the microbolometer is located.

14. A microbolometer, comprising:
a sensitive material comprising a first compound, comprising vanadium oxide, and an additional chemical element comprising arsenic, germanium, silicon, and/or phosphorus, and excluding nitrogen,
wherein the sensitive material is amorphous,
wherein the sensitive material has an electrical resistivity at ambient temperature in a range of from 0.1 to 30 Ω·cm,
wherein the sensitive material has a homogeneous chemical composition, and
wherein the sensitive material comprises an amount of the additional chemical element, defined as a ratio of a number of atoms of the additional chemical element to a number of atoms of vanadium, at least 0.012 in case of arsenic, at least 0.04 in case of germanium and silicon, and at least 0.12 in case of phosphorus.

15. The microbolometer of claim 14 , comprising an amount of oxygen, defined as a ratio of a number of oxygen atoms to a number of vanadium atoms, is in a range of from 1.42 to 1.94.

16. The microbolometer of claim 14 , wherein the sensitive material is covered by a protective layer comprising silicon nitride.

17. A device configured for detecting electromagnetic radiation, the device comprising:
more than one of the microbolometer of claim 14 , as an array of microbolometers,
wherein the microbolometers are arranged in at least one hermetic cavity delimited by an encapsulation structure transparent to the electromagnetic radiation to be detected, the encapsulation structure comprising a layer comprising amorphous silicon.

18. A detection device of claim 17 , comprising:
a getter material located in the hermetic cavity.

19. The microbolometer of claim 14 , comprising an amount of oxygen, defined as a ratio of a number of oxygen atoms to a number of vanadium atoms, is in a range of from 1.37 to 1.99.

20. The microbolometer of claim 14 , comprising an amount of oxygen, defined as a ratio of a number of oxygen atoms to a number of vanadium atoms, is in a range of from 1.47 to 1.89.

Assignees

• Commissariat Energie Atomique
• Lynred

Inventors

• Pelenc Denis
• Badano Giacomo
• Cardoso Alexi
• Guillaumont Marc

Classifications

• H10N15/15

  Thermoelectric active materials · CPC title

• G01J5/20

  using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices · CPC title

• G01J5/045 Primary

  Sealings; Vacuum enclosures; Encapsulated packages; Wafer bonding structures; Getter arrangements (getter arrangements per se H10W76/48, H10P36/03) · CPC title

• G01J5/0853

  having infrared absorbers other than the usual absorber layers deposited on infrared detectors like bolometers, wherein the heat propagation between the absorber and the detecting element occurs within a solid · CPC title

• G01J5/046 Primary

  Materials; Selection of thermal materials · CPC title