Use of vanadium oxide in microbolometer sensors

• US 5,450,053 A
• Filed: 06/29/1993
• Issued: 09/12/1995
• Est. Priority Date: 09/30/1985
• Status: Expired

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Wood, R. Andrew
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US08/085,243
• Time in Patent Office: 805 Days
• Field of Search: 250/370.14, 250/334, 250/250, 343/700, 338/14, 338/18, 338/22
• US Class Current: 338/18
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 15/02 Refracting or diffracting devices, e.g. lens, prism
• CPC Class Codes: H01Q 19/062 for focusing
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 5/42 using two or more imbricated arrays H01Q5/49 takes precedence
• CPC Class Codes: H01Q 9/065 Microstrip dipole antennas patch antenna H01Q9/0407
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence

Abstract

In a microbolometer infrared radiation sensor, a detector material (VO₂) having a high thermal coefficient of resistance to increase the sensitivity of the apparatus.

Claims

1. An infrared radiation detector comprising in combination:

a semiconductor body having a depression formed in a first surface of the body;

a thin film dielectric member attached to the first surface at least at one location and positioned to suspend the dielectric member as a thermally isolated structure over said depression; and

,

a thin film layer of vanadium oxide embedded in said dielectric member over said depression, said thin film layer having a high temperature coefficient of resistance; and

, contacts to said thin film layer of vanadium oxide adapted to be connected to a measuring circuit.

2. The detector according to claim 1 in which the thin film layer of vanadium oxide is of a thickness <

1000 angstroms.

3. The detector according to claim 1 in which the thin film layer of vanadium oxide has a resistivity on the order of 1000 ohms per square.

4. The detector according to claim 1 in which the thin film dielectric is of silicon nitride.

5. The detector according to claim 1 in which the semiconductor body is of single crystalline silicon.

6. The infrared detector according to claim 1 further comprising:

an antenna member coupled to the thin film layer of vanadium oxide.

7. The detector according to claim 6 wherein the antenna member comprises a metallic conductor shaped to optimize electromagnetic radiation of a predetermined wavelength.

8. The detector according to claim 7 wherein the antenna member comprises a dipole antenna disposed upon the thin film dielectric member.

9. The detector according to claim 8 further comprising an electrically conducting ground plane disposed on a second surface of the semiconductor body opposite the first surface of the semiconductor body.

10. The detector according to claim 9, wherein the ground plane is composed of copper.

11. The detector according to claim 10, wherein the ground plane is a thickness effective to reflect radiation incident on the first surface of the semiconductor body back through the semiconductor body and toward the antenna member.

12. The detector according to claim 11, wherein the copper ground plane is approximately 2000 Angstroms thick.

13. The detector of claim 8 wherein the antenna member comprises generally a bow-tie shape and wherein the bow-tie shaped antenna is electrically coupled to the thin film layer of vanadium oxide at the center, or "knot," of the bow-tie shaped antenna.

14. An infrared radiation detector comprising in combination:

a thin film resistor of vanadium oxide encapsulated in thin film dielectric;

a semiconductor body having a depression therein;

the encapsulated thin film resistor of vanadium oxide and thin film dielectric forming a thin film member bridged across the depression so that at least a major portion of the thin film resistor is out of contact with the semiconductor body; and

,

contacts to said thin film resistor adapted to be connected to a measuring circuit.

15. The detector according to claim 14 in which the thin film layer of vanadium oxide is of a thickness <

1000 angstroms.

16. The detector according to claim 14 in which the thin film layer of vanadium oxide has a resistivity on the order of 1000 ohms per square.

17. The detector according to claim 14 in which the thin film dielectric is of silicon nitride.

18. The detector according to claim 14 in which the semiconductor body is of single crystalline silicon.

19. An infrared radiation detector comprising in combination:

a single crystalline silicon substrate having a depression formed in a first surface of the substrate;

a thin film silicon nitride member attached to the first surface at least at one location and positioned to be suspended over said depression as a thermally isolated structure;

a thin film layer of vanadium oxide embedded in said silicon nitride member, said thin film layer having a high temperature coefficient of resistance; and

,

contacts to said thin film layer of vanadium oxide adapted to be connected to a measuring circuit.

20. An infrared radiation detector comprising in combination:

a thin film resistor of vanadium oxide embedded in a thin film silicon nitride member;

a silicon substrate having a depression in the major surface thereof;

the thin film resistor and the thin film silicon nitride member forming a thin film member fastened to the surface and bridged across the depression so that at least a major portion of the thin film resistor is out of contact with the substrate; and

,

contacts on said thin film resistor adapted to be connected to a measuring circuit.

21. An infrared detector element comprising:

a cavity in a semiconductor structure across one surface of which is suspended a resistor of vanadium oxide being suspended and supported by a thin film of dielectric material,

said suspension being disposed such that at least a major portion of said vanadium oxide resistor is out of substantial thermal contact with said semiconductor structure.

22. An infrared detector as set forth in claim 21 wherein said vanadium oxide resistor is a thin film resistor.

23. The infrared detector according to claim 21, further comprising an antenna member coupled to the thin film layer of vanadium oxide.

24. An infrared radiation detector element comprising a semiconductor structure having a cavity across which is suspended a highly sensitive detector material which has a thermal coefficient of resistance greater than metal, a film thickness of less than 1000 Å

, and having film impedance in the range of 100 to 100,000 ohms, said detector material disposed upon a layer of a dielectric material which supports said highly sensitive detector material so that a major portion of said highly sensitive detector material is out of contact with said semiconductor structure.