Source/drain feature separation structure
View Patent ↗Structures and methods including a waveguide having a cladding layer surrounding a core layer disposed over a substrate, a cavity extending into the substrate adjacent the waveguide, a fiber disposed in the cavity, and an isolation space extending into the substrate and disposed under the waveguide. A plurality of holes may extend through the cladding layer adjacent the core layer.
1. A method of fabricating a structure, comprising:
forming a waveguide having a core layer and a cladding layer over a substrate;
forming a masking element over the substrate, wherein the masking element has a first opening defining a cavity and a plurality of second openings defining a plurality of release holes;
etching the cladding layer under the first opening and the plurality of second openings to concurrently form the plurality of release holes and an upper portion of the cavity; and
etching the substrate under the plurality of release holes to form an isolation space.
2. The method of claim 1 , wherein the etching the substrate further comprises etching the substrate to extend the upper portion of the cavity to form a lower portion of the cavity.
3. The method of claim 1 , wherein the etching the cladding layer is an anisotropic etch process.
4. The method of claim 3 , wherein the etching the substrate is an isotropic etch process.
5. The method of claim 1 , wherein the forming the plurality of release holes includes forming the release holes on a first side and a second side of the core layer in a top view.
6. A method of fabricating a structure, comprising:
forming a first cladding layer over a substrate;
forming a core element;
forming a second cladding layer over the core element;
forming a masking element over the second cladding layer, wherein the masking element has a first opening defining a cavity and a plurality of second openings defining a plurality of release holes;
etching the second cladding layer under the first opening and the plurality of second openings to concurrently form the plurality of release holes and an upper portion of the cavity; and
etching the substrate under the plurality of release holes to form an isolation space.
7. The method of claim 6 , wherein the etching the second cladding layer further comprises etching the first cladding layer.
8. The method of claim 7 , wherein the etching further includes etching the substrate to extend the upper portion of the cavity to form a lower portion of the cavity.
9. The method of claim 6 , wherein the etching the first cladding layer is an anisotropic etch process.
10. The method of claim 6 , further comprising: positioning a fiber in the cavity.
11. The method of claim 6 , further comprising:
determining a positioning of a fiber element associated with a wave guide including the first cladding layer, the core element and the second cladding layer, wherein the determining the positioning includes determining a cavity depth.
12. The method of claim 11 , further comprising:
determining an etching process parameter to achieve the cavity depth to define the etching the second cladding layer.
13. The method of claim 6 , further comprising:
defining a release hole configuration to achieve the isolation space.
14. The method of claim 13 , wherein the defining the release hole configuration includes determining a first number of release holes on a first side of the core element and the first number of release holes on a second side of the core element.
15. The method of claim 13 , wherein the defining the release hole configuration includes defining a first release hole of the plurality of release holes on a first side of the core element in a top view, a second release hole of the plurality of release holes on a second side of the core element in the top view, wherein the first and second release holes are rectangular.
16. A method of fabricating a waveguide, comprising:
forming the waveguide having a core layer, a first cladding layer and a second cladding layer over a substrate;
performing a first etching process to etch the first cladding layer and the second cladding layer to concurrently form a plurality of release holes and an upper region of a cavity;
after etching performing the first etching process, performing a second etching process etching the substrate under the plurality of release holes to form an isolation space and a lower region of the cavity; and
positioning a fiber in the cavity, the fiber extending from the upper region to the lower region.
17. The method of claim 16 , wherein the isolation space is contiguous with the plurality of release holes.
18. The method of claim 16 , where the performing the first etching process includes forming a first release hole of the plurality of release holes on a first side of the core layer in a top view and a second release hole of the plurality of release holes on a second side of the core layer in the top view.
19. The method of claim 16 , wherein the isolation space is contiguous with the lower region of the cavity.
20. The method of claim 16 , wherein the second etching process includes forming a curvilinear surface of the substrate.