PHOTODETECTOR ELEMENT

• US 20110018087A1
• Filed: 07/13/2010
• Published: 01/27/2011
• Est. Priority Date: 07/13/2009
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: LE PERCHEC, Jérôme, BOUTAMI, Salim, ESPIAU DE LAMAESTRE, Roch
• Granted Patent: US 8,125,043 B2
• Time in Patent Office: Days
• US Class Current: 257/442
• CPC Class Codes: H01L 31/101 Devices sensitive to infrared, visible or ultraviolet radiation
• CPC Class Codes: H01L 31/1032 the devices comprising active layers formed only by AIIBVI compounds, e.g. HgCdTe IR photodiodes

Abstract

An element of photodetection of a radiation having a wavelength in vacuum close to a value λ₀, including:

• • a semiconductor layer of index ns and of a thickness ranging between λ₀/4 ns and λ₀/20 ns;
  • on one side of the semiconductor layer, a first medium of index n1 smaller than ns, transparent to said wavelength;
  • on the other side of the semiconductor layer:
    • a region of a second medium of index n2 smaller than ns, having a width L substantially equal to λ₀/ns and,
    • on either side of said region, a third medium, of index n3 greater than index n2, forming a reflective interface with the second medium.

Claims

1. An element of photodetection of a radiation having a wavelength in vacuum close to a value λ

₀, comprising;

a semiconductor layer (1) of index ns and of a thickness ranging between λ

₀/4 ns and λ

₀/20 ns;

on one side of the semiconductor layer, a first medium (3) of index n1 smaller than ns, transparent to said wavelength;

on the other side of the semiconductor layer;

a region (5) of a second medium (6) of index n2 smaller than ns, having a width L substantially equal to λ

₀/ns, and

on either side of said region, a third medium (7), of index n3 greater than index n2, forming a reflective interface with the second medium.

2. The photodetector element of claim 1, wherein the semiconductor layer (1) has a thickness ranging between λ

₀/4 ns and λ

₀/10 ns.

3. The photodetector element of claim 1, wherein the second medium (6) is identical to the first medium (3).

4. The photodetector element of claim 1, wherein the second medium (6) has an index greater than the index of the first medium (3).

5. The photodetector element of claim 1, wherein the third medium (7) is metallic.

6. The photodetector element of claim 5, wherein the third medium (7) has a thickness greater than λ

₀/10.

7. The photodetector element of claim 1, wherein an HgCdTe semiconductor layer is formed on a CdTe substrate, the second medium also being CdTe and the third medium being gold.

8. An assembly of photodetector elements of claim 1, connected in parallel to form a photodetector of large dimension.

9. The assembly of photodetector elements of claim 1, connected separately to form a pixel array.

10. The assembly of photodetector elements of any of the foregoing claims, comprising photodetector elements, capable of operating at identical or different wavelengths.