Pixel isolation elements, devices and associated methods

• US 9,905,599 B2
• Filed: 06/23/2015
• Issued: 02/27/2018
• Est. Priority Date: 03/22/2012
• Status: Active Grant

• Current Assignee: SiOnyx, LLC (DC Capital Partners, LLC)
• Original Assignee: SiOnyx, LLC (DC Capital Partners, LLC)
• Inventors: Pralle, Martin U., McKee, Jeffrey, Sickler, Jason
• Primary Examiner(s): Pham, Long
• Application Number:
  US14/747,875
• Publication Number:
  US 20150372040A1
• Time in Patent Office: 980 Days
• CPC Class Codes: H01L 27/14607 Geometry of the photosensitive area
• CPC Class Codes: H01L 27/1462 Coatings
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14629 Reflectors
• CPC Class Codes: H01L 27/1463 Pixel isolation structures
• CPC Class Codes: H01L 27/14645 Colour imagers
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H01L 27/14689 MOS based technologies

Abstract

Light trapping pixels, devices incorporating such pixels, and various associated methods are provided. In one aspect, for example, a light trapping pixel device can include a light sensitive pixel having a light incident surface, a backside surface opposite the light incident surface, and a peripheral sidewall disposed into at least a portion of the pixel and extending at least substantially around the pixel periphery. The pixel can also include a backside light trapping material substantially covering the backside surface and a peripheral light trapping material substantially covering the peripheral sidewall. The light contacting the backside light trapping material or the peripheral light trapping material is thus reflected back toward the pixel.

Claims

1. A light trapping device, comprising:

at least one light sensitive pixel having a light incident surface, a backside surface opposite the light incident surface, and a peripheral sidewall extending at least partially around the pixel periphery;

a backside light trapping material at least partially covering the backside surface;

a peripheral light trapping material substantially covering the peripheral sidewall, wherein said peripheral light trapping material is doped with a dopant to create a surface field; and

a reflective layer coupled to the light incident side and having an aperture to allow entry of light into the pixel;

wherein the reflective layer is operable to reflect at least a portion of light impinging thereupon from inside the pixel back into the pixel back into the pixel.

2. The device of claim 1, wherein at least one of the backside light trapping material and the peripheral light trapping material reflects light incident thereon back into the pixel.

3. The device of claim 1, wherein said peripheral light trapping material has a refractive index of less than about 2.1.

4. The device of claim 1, wherein said peripheral light trapping material includes a member selected from the group consisting of an oxide, a nitride, oxynitrides, a gas, at least a partial vacuum, and combinations thereof.

5. The device of claim 4, wherein said peripheral light trapping material is selected from the group consisting of silicon oxide, silicon nitride, silicon dioxide, and combinations thereof.

6. The device of claim 1, wherein the dopant is boron or antimony.

7. The device of claim 1, wherein the peripheral sidewall extends completely around the pixel periphery.

8. The device of claim 1, wherein the peripheral sidewall extends from the light incident surface to the backside surface.

9. The device of claim 1, wherein said aperture has an effective surface area of less than about 90% of total area of the incident light surface.

10. The device of claim 1, further comprising a lens functionally coupled to the aperture and operable to focus incident light through the aperture and into the pixel.

11. The device of claim 1, wherein at least one of the backside light trapping material and the peripheral light trapping material is a metal layer.

12. The device of claim 1, further comprising a textured region positioned to interact with light incident thereon to increase quantum efficiency of the device.

13. The device of claim 12, wherein said textured region comprises a textured film layer.

14. The device of claim 13, wherein said textured film layer comprises any of silicon dioxide, silicon nitride, amorphous silicon, polysilicon, a metal and combinations thereof.

15. The device of claim 1, wherein the peripheral light trapping material comprises any of aluminum oxide and hafnium oxide.

16. The device of claim 1, wherein the backside light trapping material substantially covers the backside surface.

17. The device of claim 1, wherein the backside light trapping material completely covers the backside surface.

18. The device of claim 1, wherein said peripheral sidewall extends through the pixel substantially from the light incident surface to the backside surface.

19. A light trapping device, comprising:

at least one light sensitive pixel having a light incident surface, a backside surface opposite the light incident surface, and a peripheral sidewall extending at least partially around the pixel periphery;

a backside light trapping material at least partially covering the backside surface;

a peripheral light trapping material substantially covering the peripheral sidewall;

a textured region positioned to interact with light incident thereon to increase quantum efficiency of the device; and

a reflective layer coupled to the light incident side and having an aperture to allow entry of light into the pixel;

wherein the reflective layer is operable to reflect at least a portion of light impinging thereupon from inside the pixel back into the pixel back into the pixel.

20. The device of claim 19, wherein at least one of the backside light trapping material and the peripheral light trapping material reflects light incident thereon back into the pixel.

21. The device of claim 19, wherein said peripheral light trapping material has a refractive index of less than about 2.1.

22. The device of claim 19, wherein said peripheral light trapping material includes a member selected from the group consisting of an oxide, a nitride, oxynitrides, a gas, at least a partial vacuum, and combinations thereof.

23. The device of claim 22, wherein said peripheral light trapping material is selected from the group consisting of silicon oxide, silicon nitride, silicon dioxide, and combinations thereof.

24. The device of claim 19, wherein said peripheral light trapping material is doped with a dopant to create a surface field.

25. The device of claim 24, wherein the dopant is boron or antimony.

26. The device of claim 19, wherein the peripheral sidewall extends completely around the pixel periphery.

27. The device of claim 19, wherein the peripheral sidewall extends from the light incident surface to the backside surface.

28. The device of claim 19, wherein said aperture has an effective surface area of less than about 90% of total area of the incident light surface.

29. The device of claim 19, further comprising a lens functionally coupled to the aperture and operable to focus incident light through the aperture and into the pixel.

30. The device of claim 19, wherein at least one of the backside light trapping material and the peripheral light trapping material is a metal layer.

31. The device of claim 19, wherein said textured region comprises a textured film layer.

32. The device of claim 31, wherein said textured film layer comprises any of silicon dioxide, silicon nitride, amorphous silicon, polysilicon, a metal and combinations thereof.

33. The device of claim 19, wherein the peripheral light trapping material comprises any of aluminum oxide and hafnium oxide.

34. The device of claim 19, wherein the backside light trapping material substantially covers the backside surface.

35. The device of claim 19, wherein the backside light trapping material completely covers the backside surface.

36. The device of claim 19, wherein said peripheral sidewall extends through the pixel substantially from the light incident surface to the backside surface.