Integrated bound-mode spectral/angular sensors

Patent metadata

Field	Value
Publication number	US-9766123-B2
Application number	US-201515317592-A
Country	US
Kind code	B2
Filing date	Jun 9, 2015
Priority date	Jun 9, 2014
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A 2-D sensor array includes a semiconductor substrate and a plurality of pixels disposed on the semiconductor substrate. Each pixel includes a coupling region and a junction region, and a slab waveguide structure disposed on the semiconductor substrate and extending from the coupling region to the region. The slab waveguide includes a confinement layer disposed between a first cladding layer and a second cladding layer. The first cladding and the second cladding each have a refractive index that is lower than a refractive index of the confinement layer. Each pixel also includes a coupling structure disposed in the coupling region and within the slab waveguide. The coupling structure includes two materials having different indices of refraction arranged as a grating defined by a grating period. The junction region comprises a p-n junction in communication with electrical contacts for biasing and collection of carriers resulting from absorption of incident radiation.

First claim

What is claimed is:

1. A 2-D sensor array, comprising:
a semiconductor substrate,
a plurality of pixels disposed on the semiconductor substrate, wherein each of the plurality of pixels comprise:
at least one coupling region and at least one junction region;
a slab waveguide structure disposed on the semiconductor substrate and extending from the at least one coupling region to the at least one junction region, and comprising a confinement layer disposed between a first cladding layer and a second cladding layer, wherein the first cladding and the second cladding each have a refractive index that is lower than a refractive index of the confinement layer; and
at least one coupling structure disposed in the coupling region and within the slab waveguide, the coupling structure comprising at least two materials having different indices of refraction, and arranged as a grating defined by a grating period,
wherein the junction region comprises a p-n junction in communication with electrical contacts for biasing and collection of carriers resulting from absorption of incident radiation.

2. The 2-D sensor array of claim 1 , further comprising electronics in electrical communication with the p-n junction, and wherein the p-n junction is biased to collect photogenerated carriers.

3. The 2-D sensor array of claim 1 , wherein the at least one coupling structure comprises a first dielectric grating positioned in the coupling region for coupling incident light into the slab waveguide and a second dielectric grating positioned in the slab waveguide region over the junction region for coupling light from the waveguide into the junction region.

4. The 2-D sensor array of claim 3 , wherein the second dielectric grating comprises a coupling constant that is higher than that of the first dielectric grating such that the second dielectric grating out-couples light into the p-n junction over a smaller spatial extent than that of the coupling region.

5. The 2-D sensor array of claim 3 , wherein at least two of the plurality of pixels have different grating periods.

6. The 2-D sensor array of claim 3 , wherein the first dielectric grating comprises a curved grating in the coupling region.

7. The 2-D sensor array of claim 3 , wherein the first dielectric grating comprises a chirped and curved grating in the coupling region.

8. The 2-D sensor array of claim 3 , wherein the first dielectric grating comprises a plurality of superimposed curved gratings, wherein at least two of the plurality of superimposed curved gratings have different pitches, and wherein the second grating comprises a plurality of gratings corresponding to each of the plurality of superimposed curved gratings.

9. The 2-D sensor array of claim 8 , wherein the junction region comprises a plurality of junction regions.

10. The 2-D sensor array of claim 3 , wherein the first dielectric grating comprises a cross-grating in the coupling area, the cross-grating comprising a first pitched grating with a first pitch and a second pitched grating with a second pitch, the second pitch grating arranged orthogonally to the first pitched grating,
wherein at least one junction region comprises a first junction region and a second junction region, and
wherein the second dielectric grating comprises a first out-coupling grating in the first junction region to accept waveguide light coupled by the first pitched grating and a second out-coupling grating in the second junction region to accept waveguide light coupled by the second pitched grating.

11. The 2-D sensor array of claim 3 , wherein the first dielectric grating comprises a plurality of overlapping chirped and curved gratings in the coupling region,
wherein the at least one junction region comprises a plurality of junction regions, and
wherein the second dielectric region comprises a plurality of junction gratings, each of the junction gratings disposed in a respective one of the plurality of junction regions and having a respective one of an angular/spectral response.

12. The 2-D sensor array of claim 1 , further comprising a metal block disposed above the slab waveguide to shield the p-n junction from direct illumination.

13. The 2-D sensor array of claim 12 , further comprising a dielectric spacer disposed between the metal block and the slab waveguide.

14. The 2-D sensor array of claim 12 , wherein the at least one coupling structure comprises a first dielectric grating positioned in the coupling region for coupling incident light into the slab waveguide and a second dielectric grating in the junction region disposed between the metal block and a localized junction area of the semiconductor substrate.

15. The 2-D sensor array of claim 12 , wherein a portion of the substrate disposed under the metal block comprises a raised portion that extends the p-n junction into the first cladding layer.

16. The 2-D array of claim 1 , the p-n junction comprises a first semiconductor layer doped with a first carrier type and comprising a plurality of posts, and a second semiconductor layer doped with a second carrier type configured with a plurality of holes extending through the second semiconductor layer and configured in a honeycomb pattern,
wherein at least one of the posts extends through a corresponding one of the plurality of holes in the honeycomb pattern;
wherein the honeycomb pattern comprises a plurality of edge portions, each of the plurality of edge portions comprising a respective one of a depletion region area.

17. The 2-D sensor array of claim 1 , wherein the 2-D sensor array has a spectral range of about 20 nm to about 50 nm over 6 to 15 spectral ranges within the 400 nm to 700 nm visible spectrum.

18. A CMOS-compatible photodetector comprising:
a first semiconductor layer doped with a first carrier type and comprising a plurality of posts, and a second semiconductor layer doped with a second carrier type configured with a plurality of holes extending through the second semiconductor layer, wherein at least one of the posts extends through a corresponding one of the plurality of holes in a honeycomb pattern, wherein the honeycomb pattern comprises a plurality of edge portions, each of the plurality of edge portions comprising a respective one of a depletion region area.

19. The CMOS-compatible photodetector of claim 18 , wherein the honeycomb structure comprises a single p-n junction.

20. A method of detecting electromagnetic radiation, comprising:
providing a 2-D sensor array, comprising:
a semiconductor substrate comprising a plurality of pixels,
wherein each of the plurality of pixels comprise:
at least one coupling region and at least one junction region,
a slab waveguide structure disposed on the semiconductor substrate and extending from the coupling region to the junction region, and
a localized semiconductor layer forming at least one p-n junction with the semiconductor substrate in the junction region,
wherein the slab waveguide comprises a confinement layer disposed between a first cladding layer and a second cladding layer, wherein the first cladding and the second cladding each have a refractive index that is lower than a refractive index of the confinement layer, and
at least one grating disposed in the slab waveguide, the at least one grating comprising a grating period;
coupling incoming light into the slab waveguide at the coupling region;
propagating the light to the region over the junction area;
decoupling the light such that it enters the junction region; and
converting the light into at

Assignees

• Stc Unm

Inventors

• Brueck Steven R J
• Neumann Alexander
• Zarkesh-Ha Payman

Classifications

• G01J1/06 Primary

  Restricting the angle of incident light · CPC title

• G02B6/122

  Basic optical elements, e.g. light-guiding paths · CPC title

• G01J3/1895

  using fiber Bragg gratings or gratings integrated in a waveguide · CPC title

• G02B2006/12107

  Grating · CPC title

• G01J3/0218

  using optical fibers · CPC title