Nanopore sensor device
A pair of electrode plates can be provided by directional deposition and patterning of a conductive material on sidewalls of a template structure on a first dielectric layer. An electrode line straddling the center portion is formed. A dielectric spacer and a conformal conductive layer are subsequently formed. Peripheral electrodes laterally spaced from the electrode line are formed by pattering the conformal conductive layer. After deposition of a second dielectric material layer that encapsulates the template structure, the template structure is removed to provide a cavity that passes through the pair of electrode plates, the electrode line, and the peripheral electrodes. A nanoscale sensor thus formed can electrically characterize a nanoscale string by passing the nanoscale string through the cavity while electrical measurements are performed employing the various electrodes.
1. A method of forming a sensor structure, said method comprising:
forming a template structure on a first dielectric material layer,
forming an electrode line straddling said template structure;
forming a dielectric spacer around said electrode line;
forming peripheral electrodes laterally spaced from said electrode line by said dielectric spacer;
forming a second dielectric material layer over said template structure; and
removing said template structure selective to said first and second dielectric material layers to form a cavity, wherein a sensor structure comprising said cavity and at least said electrode line is formed.
2. The method of claim 1 , wherein said peripheral electrodes are formed by:
depositing a conformal conductive layer on said dielectric spacer; and
patterning said conformal conductive layer into said peripheral electrodes.
3. The method of claim 2 , wherein said patterning of said conformal conductive layer comprises:
forming a photoresist layer over said conformal conductive layer;
patterning said photoresist layer such that a remaining portion of said photoresist layer straddles said electrode line; and
performing an anisotropic etch on said conformal conductive layer employing said patterned photoresist layer as an etch mask.
4. The method of claim 3 , wherein remaining portions of said conformal conductive layer after said anisotropic etch include:
portions of said conformal conductive layer underneath said photoresist layer; and
vertical portions of said conformal conductive layer that are not covered by the lithographically patterned photoresist layer remain after said anisotropic etching.
5. The method of claim 3 , further comprising removing a portion of said conformal conductive layer from above a top surface of said electrode line after said anisotropic etch, wherein two remaining disjoined portions of said conformal conductive layer constitute said peripheral electrodes.
6. The method of claim 5 , wherein said second dielectric material layer are formed over said conformal conductive layer, and said method further comprises physically exposing a top surface of said portion of said conformal conductive layer by forming a cavity in said conformal conductive layer, wherein said portion of said conformal conductive layer is removed by an etch.
7. The method of claim 6 , further comprising filling said cavity with a dielectric fill material, wherein said dielectric fill material is deposited directly on said electrode line.
8. The method of claim 3 , wherein said remaining portion of said photoresist layer cover horizontal portions of said conformal conductive layer contacting said first dielectric material layer.
9. The method of claim 2 , wherein said conformal conductive layer is deposited directly on a top surface of said electrode line.
10. The method of claim 2 , wherein said conformal conductive layer is deposited directly on outer sidewall surfaces of said dielectric spacer.
11. The method of claim 2 , wherein said conformal conductive layer is deposited directly on a top surface of said first dielectric material layer.
12. A method of forming a sensor structure, said method comprising:
forming a template structure on a first dielectric material layer, wherein template structure comprises:
a uniform width semiconductor region having a uniform width throughout;
a first tapered semiconductor region adjoined to said uniform width semiconductor region at a proximal end thereof and having a first variable width that increases with distance from said uniform width semiconductor region; and
a second tapered semiconductor region adjoined to said uniform width semiconductor region at a proximal end thereof and having a second variable width that increases with distance from said uniform width semiconductor region;
forming an electrode line straddling said template structure;
forming a second dielectric material layer over said template structure; and
removing said template structure selective to said first and second dielectric material layers to form a cavity, wherein a sensor structure comprising said cavity and at least said electrode line is formed.
13. A method of forming a sensor structure, said method comprising:
forming a template structure on a first dielectric material layer,
forming an electrode line straddling said template structure;
forming a dielectric spacer around said electrode line;
forming peripheral electrodes laterally spaced from said electrode line by said dielectric spacer;
forming a second dielectric material layer over said template structure;
forming at least one via cavity through said second dielectric material layer, wherein a surface of said template structure is physically exposed at a bottom of each of said at least one via cavity; and
removing said template structure selective to said first and second dielectric material layers to form a cavity that is contiguously connected to said at least one via cavity, wherein a sensor structure comprising said cavity and at least said electrode line is formed.
14. The method of claim 13 , wherein said peripheral electrodes are formed by:
depositing a conformal conductive layer on said dielectric spacer; and
patterning said conformal conductive layer into said peripheral electrodes.
15. The method of claim 14 , wherein said patterning of said conformal conductive layer comprises:
forming a photoresist layer over said conformal conductive layer;
patterning said photoresist layer such that a remaining portion of said photoresist layer straddles said electrode line; and
performing an anisotropic etch on said conformal conductive layer employing said patterned photoresist layer as an etch mask.
16. The method of claim 15 , wherein remaining portions of said conformal conductive layer after said anisotropic etch include:
portions of said conformal conductive layer underneath said photoresist layer; and
vertical portions of said conformal conductive layer that are not covered by the lithographically patterned photoresist layer remain after said anisotropic etching.
17. The method of claim 15 , further comprising removing a portion of said conformal conductive layer from above a top surface of said electrode line after said anisotropic etch, wherein two remaining disjoined portions of said conformal conductive layer constitute said peripheral electrodes.
18. The method of claim 14 , wherein said conformal conductive layer is deposited directly on a top surface of said first dielectric material layer.
19. The method claim 13 , wherein template structure comprises:
a uniform width semiconductor region having a uniform width throughout;
a first tapered semiconductor region adjoined to said uniform width semiconductor region at a proximal end thereof and having a first variable width that increases with distance from said uniform width semiconductor region; and
a second tapered semiconductor region adjoined to said uniform width semiconductor region at a proximal end thereof and having a second variable width that increases with distance from said uniform width semiconductor region.