Front illuminated back side contact thin wafer detectors
View Patent ↗The present invention is directed toward a detector structure, detector arrays, a method of detecting incident radiation, and a method of manufacturing the detectors. The present invention comprises several embodiments that provide for reduced radiation damage susceptibility, decreased affects of cross-talk, and increased flexibility in application. In one embodiment, the present invention comprises a plurality of front side illuminated photodiodes, optionally organized in the form of an array, with both the anode and cathode contact pads on the back side. The front side illuminated, back side contact photodiodes have superior performance characteristics, including less radiation damage, less crosstalk using a suction diode, and reliance on reasonably thin wafers. Another advantage of the photodiodes of the present invention is that high density with high bandwidth applications can be effectuated.
1. A photodiode array comprising:
a substrate having at least a front side and a back side;
a plurality of photodiodes integrally formed in the substrate forming the said array;
a plurality of electrical contacts in electrical communication with said back side; and
a plurality of suction diodes positioned at selected locations within the array, wherein each of said plurality of photodiodes and suction diodes have a front surface, back surface, and side walls and wherein said side walls are covered by a first insulating layer, a first conducting layer, and a second insulating layer.
2. The array of claim 1 wherein the first insulating layer is an oxide.
3. The array of claim 1 wherein the second insulating layer is an oxide.
4. The array of claim 1 wherein the first conducting layer is doped poly-silicon.
5. The array of claim 1 wherein the second insulating layer is in physical communication with a filler.
6. The array of claim 5 wherein the filler is undoped poly-silicon.
7. The array of claim 1 wherein the substrate is encircled by a metallic ring wherein the metallic ring has silicon underneath it.
8. The array of claim 7 , wherein silicon underneath the metal ring is doped with an impurity of a selected conductivity type.
9. The array of claim 1 wherein each of said photodiodes has a middle layer juxtaposed between a front layer and a back layer.
10. The array of claim 9 wherein said middle layer comprises a doped material of n conductivity type.
11. The array of claim 9 wherein said back layer comprises an n+ layer in electrical communication with a metal to form a cathode.
12. The array of claim 9 wherein said front layer comprises a doped material of p+ conductivity type.
13. The array of claim 12 wherein front p+ layer is in electrical communication with a metal to form an anode.
14. The array of claim 9 wherein said middle layer comprises a doped material of p conductivity type.
15. The array of claim 9 wherein said back layer comprises a p+ layer in electrical communication with a metal to form an anode.
16. The array of claim 9 wherein said front layer comprises a doped material of n+ conductivity type.
17. The array of claim 16 wherein front n+ layer is in electrical communication with a metal to form a cathode.