Method of fabricating optical filters
View Patent ↗A method of fabricating optical filter is disclosed. The method includes providing the substrate and selectively etching the substrate to form a plurality of freestanding layers. A plurality of dielectric layers is disposed over an outer surface of each of the freestanding layers. The resultant optical filters may be used in a variety of applications including etalon applications.
1. A method of fabricating optical filters comprising:
providing a substrate;
etching said substrate to farm a plurality of freestanding layers; and
depositing a plurality of dielectric layers over an outer surface of each of said freestanding layers,
wherein the method forms an optical filter.
2. A method as recited in claim 1 , further comprising removing said freestanding layers and said plurality of dielectric layers from said substrate.
3. A method as recited in claim 1 , wherein said substrate is silicon.
4. A method as recited in claim 1 , wherein said freestanding layers have side surfaces in defined crystalline planes.
5. A method as recited in claim 1 , wherein said depositing is carried out using a method of the group consisting essentially of: ALD, CVD), LPCVD, PECVD and MOCVD.
6. A method as recited in claim 1 , wherein said plurality of dielectric layer further comprises 10 to 100 layers.
7. A method as recited in claim 1 , wherein said substrate is monocrystalline silicon.
8. A method as recited in claim 1 , wherein said substrate has a <110> top surface.
9. A method as recited in claim 1 , wherein said freestanding layers have sidewalls in the <111> crystalline plane.
10. A method as recited in claim 9 , wherein said planes are substantially vertical.
11. A method as recited in claim 9 , wherein said freestanding layers have a substantially trapezoidal cross-section.
12. A method as recited in claim 1 , wherein said plurality of dielectric layers is chosen from the group consisting essentially of aluminum oxide, titanium oxide, silicon oxide, cesium oxide and tantalum oxide.
13. A method as recited in claim 1 , wherein said freestanding layers are silicon and the method further comprises oxidizing said silicon prior to depositing said plurality of dielectric layers.
14. A method of fabricating an optical etalon, the method comprising:
providing a substrate;
selectively etching said substrate to form at least two substantially parallel freestanding layers and handles; and
depositing a plurality of dielectric layers over an outer surface of said freestanding layers,
wherein the method fonna an optical etalon.
15. A method as recited in claim 14 , wherein said freestanding layers have side surfaces in defined crystalline planes.
16. A method as recited in claim 14 , wherein said depositing is carried out using a method of the group consisting essentially of: ALD, CVD, LPCVD, PECVD and MOCVD.
17. A method as recited in claim 14 , wherein a distance between said at least two freestanding layers is substantially fixed.
18. A method as recited in claim 14 , wherein a distance between said at least two freestanding layers is variable.
19. A method as recited in claim 18 , further comprising depositing a layer of transparent conductive material over said at least two freestanding layers.
20. A method as recited in claim 14 , wherein said plurality of dielectric layers is chosen from the group consisting essentially of aluminum oxide, titanium oxide, silicon oxide, cesium oxide and tantalum oxide.
21. A method of fabricating an etalon, the method comprising:
providing a substrate;
selectively etching said substrate to form at least one freestanding layer;
depositing a plurality of dielectric layers over said at least one freestanding layer on opposed sidewalls of said freestanding layer; and
removing said freestanding layer,
wherein the method forms an etalon.
22. A method as recited in claim 21 , wherein said at least one freestanding layer has a thickness, and said thickness equals a spacing of the etalon.
23. A method as recited in claim 21 , wherein said sidewalls are in defined crystalline planes.
24. A method as recited in claim 21 , wherein said sidewalls are substantially parallel.
25. A method as recited in claim 1 , wherein said etching further comprises dry etching a plurality of hales through said substrate followed by anisotropically etching said holes.
26. A method as recited in claim 25 , wherein said anisotropic etching is a wet etching step.