Photodiode and other sensor structures in flat-panel x-ray imagers and method for improving topological uniformity of the photodiode and other sensor structures in flat-panel x-ray imagers based on thin-film electronics

1. A radiation sensor comprising:

a photoconductor detector including an electrode and a photoconductive layer, the photoconductive layer being configured to generate electron-hole pairs upon interaction with ionizing radiation;

pixel circuitry electrically connected to the electrode and configured to measure an imaging signal indicative of the electron-hole pairs generated in the photoconductive layer; and

a planarization layer disposed on the pixel circuitry between the electrode and the pixel circuitry such that the electrode is above a plane including the pixel circuitry;

wherein the electrode at least partially overlaps the pixel circuitry, and

wherein the planarization layer at least partially planarizes over a feature of the pixel circuitry to reduce a topological non-uniformity arising from the feature of the pixel circuitry in the electrode.

2. The radiation sensor of claim 1 , wherein:

the pixel circuitry comprises an array of thin-film transistors; and

the planarization layer at least partially planarizes over the array of thin-film transistors.

3. The radiation sensor of claim 1 , wherein:

the pixel circuitry comprises a via interconnect; and

the planarization layer at least partially planarizes over the via interconnect.

4. The radiation sensor of claim 3 , wherein:

the pixel circuitry further comprises a thin-film transistor, the thin-film transistor comprising a source and a drain; and

the via interconnect is connected to the source or to the drain.

5. The radiation sensor of claim 1 , wherein:

the pixel circuitry comprises an in-pixel amplifier element; and

the planarization layer at least partially planarizes over the in-pixel amplifier element.

6. The radiation sensor of claim 1 , wherein:

the pixel circuitry comprises a two-stage in-pixel amplifier element; and

the planarization layer at least partially planarizes over the two-stage in-pixel amplifier element.

7. The radiation sensor of claim 1 , wherein the planarization layer comprises a passivation layer, a dielectric layer, or an insulation layer.

8. The radiation sensor of claim 1 , wherein:

the pixel circuitry comprises address and data lines disposed underneath the photoconductor detector; and

the planarization layer is disposed on the address and data lines.

9. The radiation sensor of claim 1 , wherein the pixel circuitry comprises a via interconnect that extends through the planarization layer.

10. The radiation sensor of claim 1 , wherein the pixel circuitry comprises a silicon semiconductor, an oxide semiconductor, a chalcogenide semiconductor, a cadmium selenide semiconductor, an organic semiconductor, an organic small molecule or polymer semiconductor, carbon nanotubes, or graphene.

11. A radiation sensor comprising:

a scintillation layer configured to emit photons upon interaction with ionizing radiation;

a photodetector including an electrode and a photosensitive layer, the photosensitive layer being configured to generate electron-hole pairs upon interaction with a part of said photons;

pixel circuitry electrically connected to the electrode and configured to measure an imaging signal indicative of the electron-hole pairs generated in the photosensitive layer; and

a planarization layer disposed on the pixel circuitry between the electrode and the pixel circuitry such that the electrode is above a plane including the pixel circuitry;

wherein the electrode at least partially overlaps the pixel circuitry, and

wherein the planarization layer at least partially planarizes over a feature of the pixel circuitry to reduce a topological non-uniformity arising from the feature of the pixel circuitry in the electrode.

12. The radiation sensor of claim 11 , wherein:

the pixel circuitry comprises an array of thin-film transistors; and

the planarization layer at least partially planarizes over the array of thin-film transistors.

13. The radiation sensor of claim 11 , wherein:

the pixel circuitry comprises a via interconnect; and

the planarization layer at least partially planarizes over the via interconnect.

14. The radiation sensor of claim 13 , wherein:

the pixel circuitry further comprises a thin-film transistor, the thin-film transistor comprising a source and a drain; and

the via interconnect is connected to the source or to the drain.

15. The radiation sensor of claim 11 , wherein:

the pixel circuitry comprises an in-pixel amplifier element; and

the planarization layer at least partially planarizes over the in-pixel amplifier element.

16. The radiation sensor of claim 11 , wherein:

the pixel circuitry comprises a two-stage in-pixel amplifier element; and

the planarization layer at least partially planarizes over the two-stage in-pixel amplifier element.

17. The radiation sensor of claim 11 , wherein the planarization layer comprises a passivation layer, a dielectric layer, or an insulation layer.

18. The radiation sensor of claim 11 , wherein:

the pixel circuitry comprises address and data lines disposed underneath the photoconductor detector; and

the planarization layer is disposed on the address and data lines.

19. The radiation sensor of claim 11 , wherein the pixel circuitry comprises a via interconnect that extends through the planarization layer.

20. The radiation sensor of claim 11 , wherein the pixel circuitry comprises a silicon semiconductor, an oxide semiconductor, a chalcogenide semiconductor, a cadmium selenide semiconductor, an organic semiconductor, an organic small molecule or polymer semiconductor, carbon nanotubes, or graphene.

21. A radiation sensor comprising:

a scintillation layer configured to emit photons upon interaction with ionizing radiation;

a photodetector including an electrode and a photosensitive layer, the photosensitive layer being configured to generate electron-hole pairs upon interaction with a part of said photons;

pixel circuitry electrically connected to the electrode and configured to measure an imaging signal indicative of said electron-hole pairs generated in the photosensitive layer;

a planarization layer disposed on the pixel circuitry between the electrode and the pixel circuitry such that the electrode is above a plane including the pixel circuitry; and

a surface of the electrode at least partially overlapping the pixel circuitry and having a surface inflection above features of the pixel circuitry, the surface inflection arising from at least one of the features of the pixel circuitry;

wherein the planarization layer at least partially planarizes over the at least one of the features of the pixel circuitry.

22. The radiation sensor of claim 21 , wherein:

the pixel circuitry comprises an array of thin-film transistors; and

the planarization layer at least partially planarizes over the array of thin-film transistors.

23. The radiation sensor of claim 21 , wherein:

the pixel circuitry comprises a via interconnect; and

the planarization layer at least partially planarizes over the via interconnect.

24. The radiation sensor of claim 23 , wherein:

the pixel circuitry further comprises a thin-film transistor, the thin-film transistor comprising a source and a drain; and

the via interconnect is connected to the source or to the drain.

25. The radiation sensor of claim 21 , wherein:

the pixel circuitry comprises an in-pixel amplifier element; and

the planarization layer at least partially planarizes over the in-pixel amplifier element.

26. The radiation sensor of claim 21 , wherein:

the pixel circuitry comprises a two-stage in-pixel amplifier element; and

the planarization layer at least partially planarizes over the two-stage in-pixel amplifier element.

27. The radiation sensor of claim 21 , wherein the planarization layer comprises a passivation layer, a dielectric layer, or an insulation layer.

28. The radiation sensor of claim 21 , wherein:

the pixel circuitry comprises address and data lines disposed underneath the photoconductor detector; and

the planarization layer is disposed on the address and data lines.

29. The radiation sensor of claim 21 , wherein the pixel circuitry comprises a via interconnect that extends through the planarization layer.

30. The radiation sensor of claim 21 , wherein the pixel circuitry comprises a silicon semiconductor, an oxide semiconductor, a chalcogenide semiconductor, a cadmium selenide semiconductor, an organic semiconductor, an organic small molecule or polymer semiconductor, carbon nanotubes, or graphene.

31. A radiation sensor comprising:

a photoconductor detector including an electrode and a photoconductive layer, the photoconductive layer being configured to generate electron-hole pairs upon interaction with ionizing radiation;

pixel circuitry electrically connected to the electrode and configured to measure an imaging signal indicative of said electron-hole pairs generated in the photoconductive layer;

a planarization layer disposed on the pixel circuitry between the electrode and the pixel circuitry such that the electrode is above a plane including the pixel circuitry; and

a surface of the electrode at least partially overlapping the pixel circuitry and having a surface inflection above features of the pixel circuitry, the surface inflection arising from at least one of the features of the pixel circuitry;

wherein the planarization layer at least partially planarizes over the at least one of the features of the pixel circuitry.

32. The radiation sensor of claim 31 , wherein:

the pixel circuitry comprises an array of thin-film transistors; and

the planarization layer at least partially planarizes over the array of thin-film transistors.

33. The radiation sensor of claim 31 , wherein:

the pixel circuitry comprises a via interconnect; and

the planarization layer at least partially planarizes over the via interconnect.

34. The radiation sensor of claim 33 , wherein:

the pixel circuitry further comprises a thin-film transistor, the thin-film transistor comprising a source and a drain; and

the via interconnect is connected to the source or to the drain.

35. The radiation sensor of claim 31 , wherein:

the pixel circuitry comprises an in-pixel amplifier element; and

the planarization layer at least partially planarizes over the in-pixel amplifier element.

36. The radiation sensor of claim 31 , wherein:

the pixel circuitry comprises a two-stage in-pixel amplifier element; and

the planarization layer at least partially planarizes over the two-stage in-pixel amplifier element.

37. The radiation sensor of claim 31 , wherein the planarization layer comprises a passivation layer, a dielectric layer, or an insulation layer.

38. The radiation sensor of claim 31 , wherein:

the pixel circuitry comprises address and data lines disposed underneath the photoconductor detector; and

the planarization layer is disposed on the address and data lines.

39. The radiation sensor of claim 31 , wherein the pixel circuitry comprises a via interconnect that extends through the planarization layer.

40. The radiation sensor of claim 31 , wherein the pixel circuitry comprises a silicon semiconductor, an oxide semiconductor, a chalcogenide semiconductor, a cadmium selenide semiconductor, an organic semiconductor, an organic small molecule or polymer semiconductor, carbon nanotubes, or graphene.

41. A method for fabricating a radiation sensor, the method comprising:

forming pixel circuitry elements on a base substrate;

forming a planarization layer over the pixel circuitry elements to at least partially planarize over a feature of the pixel circuitry elements;

forming a hole in the planarization layer to expose a connection to the pixel circuitry elements;

metallizing the patterned hole;

forming a first electrode in electrical contact to the metallized hole; and

forming on the first electrode a layer sensitive to light or ionizing radiation;

wherein forming the planarization layer results in a surface of the first electrode having a reduced surface inflection arising from the feature of the pixel circuitry elements.

42. The method of claim 41 , wherein:

forming the pixel circuitry forming an array of thin-film transistors; and

forming the planarization layer comprises at least partially planarizing over the array of thin-film transistors.

43. The method of claim 41 , wherein:

forming the pixel circuitry comprises forming a via interconnect; and

forming the planarization layer comprises at least partially planarizing over the via interconnect.

44. The method of claim 41 , wherein:

forming the pixel circuitry comprises forming an in-pixel amplifier element; and

forming the planarization layer comprises at least partially planarizing over the in-pixel amplifier element.

45. The method of claim 41 , wherein:

forming the pixel circuitry comprises forming address and data lines; and

forming the planarization layer comprises forming the planarization layer on the address and data lines.

46. The method of claim 41 , wherein forming the pixel circuitry comprises forming a via interconnect that extends through the planarization layer.