Dual-band detector array

Patent metadata

Field	Value
Publication number	US-9490292-B1
Application number	US-201414214004-A
Country	US
Kind code	B1
Filing date	Mar 14, 2014
Priority date	Mar 15, 2013
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

An infrared photo-detector array and a method for manufacturing it are disclosed. The infrared photo-detector array contains a collector layer, a first absorber layer that absorbs incident light of a first wavelength band and generates first electrons and first holes, a second absorber layer that absorbs incident light of a second wavelength band and generates second electrons and second holes, and wherein the wavelengths of the incident light in the first wavelength band are shorter than the wavelengths of the incident light in the second wavelength band, and wherein the second absorber layer is laterally contiguous across at least two photo-detectors. The method disclosed teaches how to manufacture the infrared photo-detector array.

First claim

What is claimed is:

1. An infrared photo-detector array of a plurality of photo-detectors, comprising:
a collector layer:
a first absorber layer that absorbs incident light of a first wavelength band and generates first electrons and first holes;
a second absorber layer that absorbs incident light of a second wavelength band and generates second electrons and second holes; and
wherein the wavelengths of the incident light in the first wavelength band are shorter than the wavelengths of the incident light in the second wavelength band;
wherein the second absorber layer is laterally contiguous across at least two photo-detectors; and
wherein the thickness of the second absorber layer is smaller than the wavelengths of light of the second wavelength band.

2. The infrared photo-detector array of claim 1 , wherein the first absorber layer is laterally contiguous across at least two photo-detectors.

3. The infrared photo-detector array of claim 1 , further comprising one or more via-holes etched through the second absorber layer.

4. The infrared photo-detector array of claim 3 , further comprising metal contacts adjacent to the first absorber layer, wherein the metal contacts are disposed within the one or more via-holes.

5. The infrared photo-detector array of claim 3 , further comprising metal posts or metal fill within the one or more via-holes.

6. The infrared photo-detector array of claim 1 , wherein the second absorber layer conducts first electrons or first holes generated in the first absorber layer; and the second absorber layer conducts second electrons or second holes generated in the second absorber layer.

7. The infrared photo-detector array of claim 1 , wherein the collector layer comprises one or more collector regions, wherein an area, as determined by a width or a diameter, of at least one collector region is smaller than an area, as determined by a width or other lateral dimension, of at least one photo-detector.

8. The infrared photo-detector array of claim 7 , further comprising metal contacts in electrical contact with the one or more collector regions;
wherein each collector region has a metal contact in electrical contact with that collector region and associated with that collector region, and
wherein the multiple collector regions of a photo-detector and the metal contacts associated with those multiple collector regions are in electrical contact with each other.

9. The infrared photo-detector array of claim 1 , further comprising:
a first barrier structure disposed between the first absorber layer and the second absorber layer; and
a second barrier disposed between the second absorber layer and the collector layer.

10. The infrared photo-detector array of claim 9 , wherein the first absorber layer comprises a p-type material and the second absorber layer comprises an n-type material.

11. The infrared photo-detector array of claim 9 , wherein the first barrier structure blocks flow of holes between the first absorber layer and the second absorber layer.

12. The infrared photo-detector array of claim 9 , wherein the first barrier blocks flow of electrons from the second absorber layer to the first absorber layer, wherein the first barrier allows flow of electrons from the first absorber layer to the second absorber layer.

13. The infrared photo-detector array of claim 9 , wherein the second barrier blocks flow of electrons between the second absorber layer and the collector regions.

14. The infrared photo-detector array of claim 13 , wherein the second barrier allows flow of holes from the second absorber layer into the collector regions.

15. The infrared photo-detector array of claim 9 , wherein the second barrier blocks flow of holes from the collector regions into the second absorber layer.

16. The infrared photo-detector array of claim 1 , further comprising:
metal interconnect lines; and
metal bond pads;
wherein the metal interconnect lines and metal bond pads form a stepped optical reflector of the incident light.

17. The infrared photo-detector array of claim 16 , wherein the first absorber layer is disposed on a side of the second absorber layer that faces incident light, and wherein the collector layer is disposed on an opposite side of the second absorber layer.

18. The infrared photo-detector array of claim 17 , wherein the metal interconnect lines and the metal bond pads are disposed on the side of the second absorber layer away from incident light.

19. The infrared photo-detector array of claim 18 , further comprising pyramid shaped structures associated with the first absorber layer.

20. The infrared photo-detector array of claim 17 , further comprising pyramid shaped structures disposed above the first absorber layer opposite the side of the first absorber layer facing the second absorber layer.

21. The infrared photo-detector array of claim 20 , wherein the pyramid shaped structures are transparent to light of the first and second wavelength bands.

22. The infrared photo-detector array of claim 16 , further comprising a dielectric spacer disposed between the metal interconnect lines and the second absorber layer.

23. The infrared photo-detector array of claim 16 , further comprising a dielectric material disposed between collector regions and the metal interconnect lines.

24. The infrared photo-detector array of claim 16 , further comprising a dielectric material disposed between sidewalls of a via-hole and a metal post or metal fill in that via-hole.

25. The infrared photo-detector array of claim 1 , wherein the first absorber layer comprises a material with a first cutoff wavelength, the second absorber layer comprises a material with a second cutoff wavelength; and the collector layer comprise a material of a third cutoff wavelength; wherein the first cutoff wavelength is shorter than the second cutoff wavelength.

26. The infrared photo-detector array of claim 25 , wherein the third cutoff wavelength is shorter than the first cutoff wavelength.

27. The infrared photo-detector array of claim 7 , wherein at least one collector region is disposed at a center of a photo-detector.

28. The infrared photo-detector array of claim 7 , wherein at least one collector region is disposed beneath and aligned with the center of at least one pyramid shaped structure associated with a photo-detector.

29. The infrared photo-detector array of claim 1 , wherein the collector layer comprises n-type material.

Assignees

• Hrl Lab Llc
• Hrl Lab Llc

Inventors

• Yap Daniel
• Rajavel Rajesh D

Classifications

• H01L27/14652 Primary

  Electricity · mapped topic

• H01L27/14629

  Electricity · mapped topic

• H01L27/14636

  Electricity · mapped topic

• H10F39/811

  Interconnections · CPC title

• H10F39/806

  Optical elements or arrangements associated with the image sensors · CPC title