PHOTONIC SENSOR AND A METHOD OF MANUFACTURING SUCH A SENSOR

• US 20140151557A1
• Filed: 12/03/2012
• Published: 06/05/2014
• Est. Priority Date: 12/03/2012
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Lambkin, Paul Martin, Lane, William Allan
• Granted Patent: US 9,297,700 B2
• Time in Patent Office: Days
• US Class Current: 250/338.1
• CPC Class Codes: G01J 5/0225 Shape of the cavity itself or of elements contained in or suspended over the cavity
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/0831 Masks; Aperture plates; Spatial light modulators
• CPC Class Codes: G01J 5/0853 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 Class Codes: G01J 5/12 using thermoelectric elements, e.g. thermocouples
• CPC Class Codes: G01K 7/02 using thermoelectric elements, e.g. thermocouples
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof

Abstract

A photonic sensor, comprising: a platform, a temperature sensor on the platform; and a structure formed on or as part of the platform.

Claims

1. A photonic sensor, comprising:

a platform supported by at least one slender element;

a temperature sensor on the platform; and

a structure formed on or as part of the platform.

2. A sensor as claimed in claim 1, in which the structure is etched into the platform so as reduce the mass of the platform.

3. A sensor as claimed in claim 2, in which the structure comprises a plurality of voids.

4. A sensor as claimed in claim 3, in which the voids form a plurality of intersecting trenches.

5. A sensor as claimed in claim 3, in which the voids are not of uniform depth within the platform.

6. A sensor as claimed in claim 5, in which parts of some of the voids extend through a depth of the platform.

7. A sensor as claimed in claim 1, wherein the platform comprises a metal layer.

8. A sensor as claimed in claim 7, in which the platform further comprises a semiconductor layer in association with the metal layer.

9. A sensor as claimed in claim 7, wherein the platform further comprises a nitride layer.

10. A sensor as claimed in claim 8, having a plurality of column or hill like structures extending from a first side of the metal layer.

11. A sensor as claimed in claim 10, in which the plurality of column or hill like structures are formed in an intra-structure scale of less than lambda, where lambda is the maximum wavelength to be detected, and is 50×

10<sup>−

6</sup> m or less.

12. A sensor as claimed in claim 7, in which a plurality of apertures extend through the first metal layer, and through any layer disposed adjacent a second side of the metal layer.

13. A sensor as claimed in claim 1, comprising a plurality of platforms arranged in an array within an evacuated cavity bounded on a first side by a window.

14. A sensor as claimed in claim 1, in which the platform is supported by two or more slender legs, said slender legs having a combined width at an interface with the platform of less than one quarter of the periphery of the platform.

15. A sensor as claimed in claim 1, in which the temperature sensor is a thermocouple junction.

16. A temperature sensor as claimed in claim 15, in which the thermocouple junction comprises one of:

a) a polysilicon to polysilicon junction, where a doping concentration varies across the junction;

b) a SiGe to SiGe junction.

17. A sensor as claimed in claim 1, further comprising a conductor on or adjacent the platform for providing ohmic heating to the platform.

18. A sensor as claimed in claim 1, in which the temperature sensor is a temperature dependent resistor.

19. A method of forming a photonic sensor, comprising processing a portion of a semiconductor substrate so as to form a platform held to a supporting structure by at least one leg, and further comprising forming a sub-wavelength structure on an upper surface of the platform, said structure comprising either a plurality of isolated or interconnected upstanding regions.

20. A method as claimed in claim 19, in which the processing comprises masking and etching the substrate to form the platform.

21. A method as claimed in claim 20, in which the platform is further etched to form a plurality of apertures through the platform so as to under etch the platform so as to release it from contact with the underlying substrate.

22. A method as claimed in claim 19, in which the leg, or each leg, is slender.