Aluminum indium antimonide focal plane array
View Patent ↗In one embodiment, a detector includes an Al z In (1-x) Sb passivation/etch stop layer, an Al x In (1-x) Sb absorber layer disposed above the Al z n (1-z) Sb passivation/etch stop layer, and an Al y In (1-y) Sb passivation layer disposed above the Al x In (1-x) Sb absorber layer, wherein x<z and x<y. The detector further includes a junction formed in a region of the Al x In (1−x) Sb absorber layer, and a metal contact disposed above the junction and through the Al y In (1-y) Sb passivation layer.
1. A detector comprising:
an Al z In (1-z) Sb passivation/etch stop layer;
an Al x In (1-x) Sb absorber layer disposed above the Al z In (1-z) Sb passivation/etch stop layer, wherein x<z;
an Al y In (1-y) Sb passivation layer disposed above the Al x In (1-x) Sb absorber layer, wherein x<y;
a junction formed in a region of the Al x In (1-x) Sb absorber layer; and
a metal contact disposed above the junction and through the Al y In (1-y) Sb passivation layer.
2. The detector of claim 1 , wherein the Al z In (1-z) Sb passivation/etch stop layer, the Al x in (1-x) Sb absorber layer, and the Al y In (1-y) Sb passivation layer are each epitaxial layers formed consecutively during one growth run.
3. The detector of claim 1 , wherein z is between about 0.02 and about 0.13, x is between about 0.01 and about 0.1, and y is between about 0.02 and about 0.13.
4. The detector of claim 1 , wherein the Al z In (1-z) Sb passivation/etch stop layer has a thickness between about 100 angstroms and about 10,000 angstroms, the Al x In (1-x) Sb absorber layer has a thickness between about 30,000 angstroms and about 150,000 angstroms, and the Al y In (1-y) Sb passivation layer has a thickness between about 100 angstroms and about 10,000 angstroms.
5. The detector of claim 1 , wherein the junction is selected from the group consisting of a p-n junction, an n-p junction, a p-i-n junction, and a n-i-p junction.
6. The detector of claim 1 , comprising:
an overglass layer disposed above the Al y In (1-y) Sb passivation layer; and
an indium bump disposed above the metal contact and the overglass layer.
7. The detector of claim 1 , comprising:
an antireflective layer disposed below the Al x In (1-x) Sb absorber layer.
8. The detector of claim 1 , comprising:
an InSb substrate above which an InSb buffer layer, the Al z In (1-z) Sb passivation/etch stop layer, and the Al x In (1-x) Sb absorber layer are formed, wherein the InSb substrate and the InSb buffer layer are subsequently removed to expose a back surface of the Al z In (1-z) Sb passivation/etch stop layer.
9. An infrared sensor array comprising:
a two-dimensional array of detectors, each of the detectors comprising:
an Al z In (1-z) Sb passivation/etch stop layer
an Al x In (1-x) Sb absorber layer disposed above the Al z In (1-z) Sb passivation/etch stop layer, wherein x<z;
an Al y In (1-y) Sb passivation layer disposed above the Al x In (1-x) Sb absorber layer, wherein x<y;
a junction formed in a region of the Al x In (1-x) Sb absorber layer;
a metal contact disposed above the junction and through the Al y In (1-y) Sb passivation layer;
an overglass layer disposed above the metal contact; and
a bump contact disposed above the metal contact and through the overglass layer.
10. The sensor array of claim 9 , wherein the Al z In (1-z) Sb passivation/etch stop layer, the Al x In (1-x) Sb absorber layer, and the Al y In (1-y) Sb passivation layer are each epitaxial layers formed consecutively during one growth run.
11. The sensor array of claim 9 , wherein z is between about 0.02 and about 0.13, x is between about 0.01 and about 0.1, and y is between about 0.02 and about 0.13.
12. The sensor array of claim 9 , comprising:
an antireflective layer disposed below the Al x In (1-x) Sb absorber layer.
13. The sensor array of claim 9 , comprising:
an InSb substrate above which an InSb buffer layer, the Al z In (1-z) Sb passivation/etch stop layer, and the Al x In (1-x) Sb absorber layer are formed, wherein the InSb substrate and the InSb buffer layer are subsequently removed to expose a back surface, of the Al z In (1-z) Sb passivation/etch stop layer.
14. A method of fabricating a detector, the method comprising:
providing an InSb substrate;
forming, by epitaxial growth in one growth run, an Al z In (1-y) Sb passivation/etch stop layer above a surface of the InSb substrate, an Al x In (1-x) Sb absorber layer above a surface of the Al z In (1-z) Sb passivation/etch stop layer, and an Al y In (1-y) Sb passivation layer above the Al x In (1-x) Sb absorber layer, wherein x<z and x<y;
forming a junction in a region of the Al x In (1-x) Sb absorber layer;
forming a metal contact above the junction and through the Al y In (1-y) Sb passivation layer; and
removing the InSb substrate to expose the Al z In (1-z) Sb passivation/etch stop layer.
15. The method of claim 14 , wherein the Al z In (1-z) Sb passivation/etch stop layer, the Al x In (1-x) Sb absorber layer, and the Al y In (1-y) Sb passivation layer are each formed by one of molecular beam epitaxy (MBE), metal-organic condensed vapor deposition (MOCVD), or liquid phase epitaxy (LPE).
16. The method of claim 14 , wherein z is between about 0.02 and about 0.13, x is between about 0.01 and about 0.1, and y is between about 0.02 and about 0.13.
17. The method of claim 14 , wherein the Al z In (1-z) Sb passivation/etch stop layer is formed to a thickness between about 100 angstroms and about 10,000 angstroms, the Al x In (1-x) Sb absorber layer is formed to a thickness between about 30,000 angstroms and about 150,000 angstroms, and the Al y In (1-y) Sb passivation layer is formed to a thickness between about 100 angstroms and about 10,000 angstroms.
18. The method of claim 14 , wherein the InSb substrate is removed by mechanical and/or chemical etching.
19. The method of claim 14 , wherein forming the junction includes forming one of a p-n junction, an n-p junction, a p-i-n junction, or a n-i-p junction.
20. The method of claim 14 , comprising:
forming an antireflective layer over the exposed Al z In (1-z) Sb passivation/etch stop layer.