Fabrication method for photonic devices
Electro-optical devices and methods for constructing electro-optical devices such as a switch or phase shifter. An electrode layer is deposited on a substrate layer, a waveguide structure is deposited on the electrode layer, a first cladding layer is deposited on the waveguide structure, and the first cladding layer is planarized and bonded to a wafer. The substrate layer is removed and the electrode layer is etched to split the electrode layer into a first electrode separated from a second electrode. A second cladding layer is deposited on the etched electrode layer. The first and second electrodes may be composed of a material with a large dielectric constant, or they may be composed of a material with a large electron mobility. The device may exhibit a sandwich waveguide architecture where an electro-optic layer is disposed between two strip waveguides.
1. A method for constructing a device, the method comprising:
receiving a first wafer comprising a first layer stack, wherein the first layer stack comprises:
a first substrate layer;
an electrode layer disposed on the first substrate layer; and
an electro-optic layer disposed on the electrode layer;
receiving a second wafer, the second wafer comprising:
a second cladding layer;
a second substrate layer disposed on the second cladding layer; and
a second strip waveguide structure disposed within the second cladding layer;
bonding the electro-optic layer of first layer stack to the second cladding layer of the second wafer;
after bonding the electro-optic layer to the second cladding layer:
removing the first substrate layer;
etching the electrode layer to split the electrode layer into a first electrode separated from a second electrode;
depositing a first strip waveguide structure between the first and second electrodes; and
depositing a first cladding layer on the first electrode, the second electrode, and the first strip waveguide structure.
2. The method of claim 1 , further comprising:
etching the first cladding layer to expose a first portion of the first electrode and a second portion of the second electrode;
depositing a first lead on the first portion of the first electrode; and
depositing a second lead on the second portion of the second electrode.
3. The method of claim 2 ,
wherein the first lead and the second lead are deposited on an upper surface of the first portion of the first electrode and the second portion of the second electrode, respectively.
4. The method of claim 2 , further comprising:
etching the first portion of the first electrode and the second portion of the second electrode,
wherein the first lead and the second lead are deposited a first distance within respective cross sections of the first portion of the first electrode and the second portion of the second electrode, respectively.
5. The method of claim 1 , further comprising:
etching the first cladding layer to expose a first portion of the first electrode and a second portion of the second electrode;
etching the first portion of the first electrode and the second portion of the second electrode to expose respective portions of the electro-optic layer;
depositing a first lead and a second lead on the exposed portions of the electro-optic layer.
6. The method of claim 1 ,
wherein the first strip waveguide structure is composed of silicon nitride, and
wherein the second strip waveguide is composed of silicon.
7. The method of claim 1 ,
wherein the first and second strip waveguide structures are composed of silicon nitride.
8. The method of claim 1 ,
wherein the first and second strip waveguide structure are each composed of one of:
silicon nitride;
silicon dioxide; or
aluminum oxide.
9. The method of claim 1 ,
wherein the second strip waveguide structure is disposed within the second cladding layer a first distance from a surface of the second cladding layer that is bonded to the electro-optic layer, and
wherein the first distance is several nanometers.
10. The method of claim 1 , further comprising:
after depositing the first strip waveguide structure between the first and second electrodes, planarizing to remove excess material from a region above the first and second electrodes.
11. The method of claim 10 ,
wherein planarizing comprises lithographic patterning or chemical mechanical polishing (CMP).
12. A method for constructing a device, the method comprising:
receiving a first wafer comprising a first layer stack, wherein the first layer stack comprises:
a first substrate layer;
a seed layer disposed on the first substrate layer; and
an electro-optic layer disposed on the seed layer;
receiving a second wafer, the second wafer comprising:
a second cladding layer;
a second substrate layer disposed on the second cladding layer; and
a second strip waveguide structure disposed within the second cladding layer;
bonding the electro-optic layer of first layer stack to the second cladding layer of the second wafer;
after bonding the electro-optic layer to the second cladding layer:
removing the first substrate layer and the seed layer;
depositing an electrode layer on the electro-optic layer;
etching the electrode layer to split the electrode layer into a first electrode separated from a second electrode;
depositing a first strip waveguide structure between the first and second electrodes; and
depositing a first cladding layer on the first electrode, the second electrode, and the first strip waveguide structure.
13. The method of claim 12 , further comprising:
after removing the seed layer and before depositing the electrode layer, removing a portion of the electro-optic layer.
14. The method of claim 12 , further comprising:
etching the first cladding layer to expose a first portion of the first electrode and a second portion of the second electrode;
depositing a first lead on the first portion of the first electrode; and
depositing a second lead on the second portion of the second electrode.
15. The method of claim 14 ,
wherein the first lead and the second lead are deposited on an upper surface of the first portion of the first electrode and the second portion of the second electrode, respectively.
16. The method of claim 14 , further comprising:
etching the first portion of the first electrode and the second portion of the second electrode,
wherein the first lead and the second lead are deposited a first distance within respective cross sections of the first portion of the first electrode and the second portion of the second electrode, respectively.
17. The method of claim 12 , further comprising:
etching the first cladding layer to expose a first portion of the first electrode and a second portion of the second electrode;
etching the first portion of the first electrode and the second portion of the second electrode to expose respective portions of the electro-optic layer;
depositing a first lead and a second lead on the exposed portions of the electro-optic layer.
18. The method of claim 12 ,
wherein the first and second strip waveguide structure are each composed of one of:
silicon nitride;
silicon dioxide; or
aluminum oxide.
19. The method of claim 12 ,
wherein the second strip waveguide structure is disposed within the second cladding layer a first distance from a surface of the second cladding layer that is bonded to the electro-optic layer, and
wherein the first distance is several nanometers.
20. The method of claim 12 , further comprising:
after depositing the first strip waveguide structure between the first and second electrodes, planarizing to remove excess material from a region above the first and second electrodes,
wherein planarizing comprises lithographic patterning or chemical mechanical polishing (CMP).