High-absorption wide-band pixel for bolometer arrays

• US 6,621,083 B2
• Filed: 12/29/2000
• Issued: 09/16/2003
• Est. Priority Date: 12/29/2000
• Status: Expired due to Term

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Cole, Barrett E.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US09/751,338
• Publication Number:
  US 20030020017A1
• Time in Patent Office: 991 Days
• Field of Search: 250/338.1
• US Class Current: 250/338.1
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices

Abstract

A microbolometer array has pixels with a thin platform of silicon dioxide having a metal absorber layer, and having a resonant gap with a substrate reflector. The pixel resistor of vanadium oxide has low total resistance with metal contacts on opposite edges.

Claims

1. An imaging detector for infrared radiation in the approximate range of 6 to 18 micrometers, comprising an array of pixels on a common substrate, each pixel comprising:

a thermally isolated absorber platform having a thickness equal to or less than approximately 0.5 micrometer and a layer of metal, and separated from the substrate by a gap in the approximate range of 0.8 to 2.5 micrometers;

a temperature-dependent resistor disposed on the platform and having at least one pair of opposite sides;

a reflective layer on the substrate;

a set of conductors electrically coupled to the resistor along a substantial portion of the length of the opposite sides.

2. The detector of claim 1 further comprising detection circuits coupled to at least some of the conductors.

3. The detector of claim 2 where the detection circuits are disposed on the substrate.

4. The detector of claim 2 further comprising an image display.

5. The detector of claim 4 further comprising a scan generator coupled to the detection circuits for scanning the pixels in the array.

6. The detector of claim 5 where the scan generator is further coupled to the image display.

7. A microbolometer pixel comprising:

a substrate;

a platform body having a thickness less than about 0.5 micrometer and including a layer of metal for enhancing absorption;

a substantially rectangular temperature-sensitive resistor layer having a pair of opposite sides on the platform body;

a pair of arms for suspending the body over the substrate so as to form a gap therebetween;

a pair of low-resistance electrical contacts extending along substantially all the length of the pair of opposite sides.

8. The bolometer pixel of claim 7 where the resistor has further opposite sides.

9. The bolometer pixel of claim 8 where the pair of opposite sides are longer than the further opposite sides.

10. The bolometer pixel of claim 7 where the electrical contacts are a layer of metal.

11. The bolometer pixel of claim 10 where the electrical contacts are nickel chromium.

12. The bolometer pixel of claim 11 where the layer for enhancing absorption is nickel chromium.

13. The bolometer pixel of claim 10 where the substrate includes a reflecting layer on the substrate under the platform body.

14. The bolometer pixel of claim 10 where the reflecting layer is nickel chromium.

15. The bolometer pixel of claim 10 where the layer of metal forming the electrical contacts extends over substantially all the length of the arms.

16. The bolometer pixel of claim 7 where the resistor is an oxide of vanadium.

17. The bolometer pixel of claim 16 where the total resistance of the resistor is in the approximate range of 50 to 400 kiloohms.

18. The bolometer pixel of claim 17 where the total resistance of the resistor is about 100 kiloohms.

19. A microbolometer pixel comprising:

a substrate;

a platform body having a thickness less than about 0.5 micrometer and including a layer of metal for enhancing absorption;

a temperature-sensitive resistor layer having a periphery on the platform body;

a pair of arms forming a single continuous sheet with the platform body for suspending the body over the substrate so as to form a gap therebetween;

a pair of low-resistance electrical contacts extending along at least about half of the periphery of the resistor layer.

20. The bolometer pixel of claim 19 where the electrical contacts comprise a metal layer.

21. The bolometer pixel of claim 19 where the resistor is exposed directly to incident infrared radiation.

22. The bolometer pixel of claim 21 where the resistor is substantially transparent to the incident radiation.

23. The bolometer pixel of claim 19 where the platform body comprises silicon oxide and silicon nitride entirely underlying the silicon oxide.

24. The bolometer pixel of claim 23 where the layer of metal lies between the silicon oxide and the silicon nitride.