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

a photodetector including in order a first electrode, a photosensitive layer, and a photon-transmissive second electrode disposed in proximity to the scintillation layer;

said photosensitive layer configured to generate electron-hole pairs upon interaction with a part of said photons;

pixel circuitry electrically connected to the first 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 first electrode and the pixel circuitry such that the first electrode is above a plane including the pixel circuitry; and

a surface of at least one of said first electrode and said second electrode at least partially overlapping the pixel circuitry and having a surface inflection above features of the pixel circuitry.

2. The sensor of claim 1 , wherein a dark current, normalized to unit photodetector area, between the first electrode and the photon-transmissive second electrode is less than 10 pA/mm 2 .

3. The sensor of claim 1 , wherein a dark current, normalized to unit photodetector area, between the first electrode and the photon-transmissive second electrode is less than 5 pA/mm 2 .

4. The sensor of claim 3 , wherein a dark current, normalized to unit photodetector area, between the first electrode and the photon-transmissive second electrode is less than 1 pA/mm 2 .

5. The sensor of claim 1 , wherein a dark current, normalized to unit photodetector area, between the first electrode and the photon-transmissive second electrode is less than 0.5 pA/mm 2 .

6. The sensor of claim 1 , wherein said planarization layer at least partially planarizes over said features of the pixel circuitry.

7. The sensor of claim 1 , wherein said planarization layer at least partially planarizes over array features, over electrical via interconnects connecting to the source or drain of TFTs, over one-stage in-pixel amplifier elements, or over two-stage in-pixel amplifier elements, or pixels circuits that allow single photon counting.

8. The sensor of claim 1 , wherein said planarization layer comprises at least one of a passivation layer, a dielectric layer, or an insulation layer.

9. The sensor of claim 1 , further comprising: address and data lines disposed underneath the photodetector; and said planarization layer is disposed on the address and data lines and on vias of the address and data lines.

10. The sensor of claim 1 , further comprising: an electrical via interconnect extending through the planarization layer and connecting the first electrode to said pixel circuitry, wherein a surface inflection of the electrical via interconnect in contact with the photosensitive layer has a radius of curvature greater than one half micron.

11. The sensor of claim 10 , wherein said surface inflection of the electrical via interconnect has a radius of curvature greater than one micron.

12. The sensor of claim 10 , wherein said surface inflection of the electrical via interconnect has a radius of curvature greater than five microns.

13. The sensor of claim 10 , wherein said surface inflection of the electrical via interconnect has a radius of curvature greater than ten microns.

14. The sensor of claim 10 , wherein said surface inflection of the electrical via interconnect has a radius of curvature greater than one hundred microns.

15. The sensor of claim 1 , wherein the photosensitive layer comprises one of a p-i-n semiconductor stack, a n-i-p semiconductor stack, or a metal insulator semiconductor stack.

16. The sensor of claim 1 , wherein said pixel circuitry comprises one of thin film transistors, diodes, capacitors, resistors, traces, vias, control lines, address lines, and ground planes.

17. The sensor of claim 1 , wherein said pixel circuitry comprises one of an amorphous semiconductor transistor or a polycrystalline semiconductor transistor or a microcrystalline semiconductor transistor.

18. The sensor of claim 1 , wherein said pixel circuitry comprises at least one of an addressing transistor, an amplifier transistor, and a reset transistor.

19. The sensor of claim 1 , wherein said pixel circuitry comprises at least one of amorphous silicon, low temperature amorphous silicon, and microcrystalline silicon.

20. The sensor of claim 1 , wherein said pixel circuitry comprises at least one of a semiconductor, a silicon 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 photoconductor detector including in order a first electrode, a photoconductive layer, and an ionizing radiation transmissive second electrode, and said photoconductive layer configured to generate electron-hole pairs upon interaction with ionizing radiation;

pixel circuitry electrically connected to the first 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 first electrode and the pixel circuitry such that the first electrode is above a plane including the pixel circuitry; and

a surface of at least one of said first electrode and said second electrode at least partially overlapping the pixel circuitry and having a surface inflection above features of the pixel circuitry.

22. The sensor of claim 21 , wherein a dark current, normalized to unit photoconconductor detector area, between the first electrode and the second electrode is less than 10 pA/mm 2 .

23. The sensor of claim 21 , wherein a dark current, normalized to unit photoconconductor detector area, between the first electrode and the second electrode is less than 5 pA/mm 2 .

24. The sensor of claim 21 , wherein a dark current, normalized to unit photoconconductor detector area, between the first electrode and the second electrode is less than 1 pA/mm 2 .

25. The sensor of claim 21 , wherein a dark current, normalized to unit photoconconductor detector area, between the first electrode and the second electrode is less than 0.5 pA/mm 2 .

26. The sensor of claim 21 , wherein said planarization layer at least partially planarizes over said features of the pixel circuitry.

27. The sensor of claim 21 , wherein said planarization layer at least partially planarizes over array features, over electrical via interconnects connecting to the source or drain of TFTs, over one-stage in-pixel amplifier elements, or over two-stage in-pixel amplifier elements, or pixels circuits that allow single photon counting.

28. The sensor of claim 21 , wherein said planarization layer comprises at least one of a passivation layer, a dielectric layer, or an insulation layer.

29. The sensor of claim 21 , further comprising: address and data lines disposed underneath the photoconductive detector; and said planarization layer is disposed on the address and data lines and on vias of the address and data lines.

30. The sensor of claim 21 , further comprising: an electrical via interconnect extending through the planarization layer and connecting the first electrode to said pixel circuitry, wherein a surface inflection of the electrical via interconnect in contact with the photoconductive layer has a radius of curvature greater than one half micron.

31. The sensor of claim 30 , wherein said surface inflection of the electrical via interconnect has a radius of curvature greater than one micron.

32. The sensor of claim 30 , wherein said surface inflection of the electrical via interconnect has a radius of curvature greater than five microns.

33. The sensor of claim 30 , wherein said surface inflection of the electrical via interconnect has a radius of curvature greater than ten microns.

34. The sensor of claim 21 , wherein the photoconductive layer comprises at least one of VB-VIB, VB-VIIB, IIB-VIB, IIB-VB, IIIB-VB, IIIB-VIB, IB-VIB, and IVB-VIIB semiconductors.

35. The sensor of claim 21 , wherein the photoconductive layer comprises at least one of a-Se, PbI 2 , HgI 2 , PbO, CdZnTe, CdTe, Bi 2 S 3 , Bi 2 Se 3 , BiI 3 , BiBr 3 , CdS, CdSe, HgS, Cd 2 P 3 , InAs, InP, In 2 S 3 , In 2 Se 3 , Ag 2 S, PbI 4 −2 and Pb 2 I 7 −3 .

36. The sensor of claim 21 , wherein said pixel circuitry comprises one of thin film transistors, diodes, capacitors, resistors, traces, vias, control lines, address lines, and ground planes.

37. The sensor of claim 21 , wherein said pixel circuitry comprises one of an amorphous semiconductor transistor or a polycrystalline semiconductor transistor or a microcrystalline semiconductor transistor.

38. The sensor of claim 21 , wherein said pixel circuitry comprises at least one of an addressing transistor, an amplifier transistor, and a reset transistor.

39. The sensor of claim 21 , wherein said pixel circuitry comprises at least one of amorphous silicon, low temperature amorphous silicon, or microcrystalline silicon.

40. The sensor of claim 21 , wherein said pixel circuitry comprises at least one of a semiconductor, a silicon semiconductor, a chalcogenide semiconductor, a cadmium selenide semiconductor, an organic semiconductor, an organic small molecule or polymer semiconductor, carbon nanotubes, or graphene.