Nanopore well structures and methods

Abstract

A nanopore cell may include a well having a working electrode at a bottom of the well. The well may be formed within a dielectric layer, where the sidewalls of the well may be formed of the dielectric or other materials coating the walls of the dielectric layer. Various materials having different hydrophobicity and hydrophilicity can be used to provide desired properties of the cell. The nanopore in the nanopore cell can be inserted in a membrane formed over the well. Various techniques can be used for providing a desired shape and other properties e.g., of materials and processes for forming the well.

What is claimed is: 
     
         1 . A nanopore cell, comprising:
 a substrate;   a conductive layer disposed in a top portion of the substrate;   an electrode layer disposed on the conductive layer;   a dielectric layer disposed on the electrode layer;   a cavity in the dielectric layer, the cavity exposing a portion of the electrode layer; and   a well formed in the cavity, the well having a well sidewall formed by the dielectric layer and a well bottom on the exposed portion of the electrode layer,   wherein a corner between a top surface of the dielectric layer and the well sidewall is characterized by a radius of curvature r, and an angle between the top surface of the dielectric layer and the well sidewall is characterized by an angle θ.   
     
     
         2 . The nanopore cell of  claim 1 , wherein the well sidewall has a reentrant profile. 
     
     
         3 . The nanopore cell of  claim 1 , wherein the angle θ is less than 90°. 
     
     
         4 . The nanopore cell of  claim 1 , wherein the angle θ is less than 45°. 
     
     
         5 . The nanopore cell of  claim 1 , wherein the angle θ is substantially 90°. 
     
     
         6 . The nanopore cell of  claim 1 , wherein the angle θ is substantially 90°, and the radius of curvature r is less than 3 μm. 
     
     
         7 . The nanopore cell of  claim 1 , wherein the angle θ is greater than 90°. 
     
     
         8 . The nanopore cell of  claim 1 , wherein the well bottom is hydrophilic and the well sidewall is hydrophobic. 
     
     
         9 . The nanopore cell of  claim 1 , wherein the well bottom is hydrophilic, a lower portion of the well sidewall is hydrophilic, and an upper portion of the well sidewall is hydrophobic. 
     
     
         1 . The nanopore cell of  claim 1 , wherein the well bottom is hydrophilic, the well sidewall is hydrophilic, and the top surface of the dielectric layer is hydrophobic. 
     
     
         11 . The nanopore cell of  claim 1 , wherein the well sidewall has a reentrant profile, wherein the well bottom is hydrophilic and the well sidewall is hydrophobic. 
     
     
         12 . The nanopore cell of  claim 1 , wherein the well sidewall has a concave profile. 
     
     
         13 . The nanopore cell of  claim 1 , wherein the electrode layer extends to cover a lower portion of the well sidewall. 
     
     
         14 . A nanopore cell, comprising:
 a substrate;   a conductive layer disposed in a top portion of the substrate;   an electrode layer disposed on the conductive layer;   a dielectric layer disposed on the electrode layer;   a cavity in the dielectric layer, the cavity exposing a portion of the electrode layer; and   a well formed by the cavity on the exposed portion of the electrode layer, the well having the exposed portion of the electrode layer as a bottom base and sidewalls extending from a top opening to the bottom base forming a reentrant profile, wherein the bottom base is wider than the top opening.   
     
     
         15 . The nanopore cell of  claim 14 , wherein the electrode layer comprises a porous electrode layer. 
     
     
         16 . The nanopore cell of  claim 14 , wherein the electrode layer comprises a porous TiN electrode layer. 
     
     
         17 . The nanopore cell of  claim 14 , wherein the dielectric layer comprises a polyimide layer. 
     
     
         18 . The nanopore cell of  claim 14 , wherein the dielectric layer comprises a hydrophobic surface. 
     
     
         19 . The nanopore cell of  claim 14 , wherein an angle between a top surface of the well and a well sidewall is characterized by an angle θ less than 90°. 
     
     
         20 . The nanopore cell of  claim 14 , wherein an angle between a top surface of the well and a well sidewall is characterized by an angle θ less than 45°. 
     
     
         21 . The nanopore cell of  claim 14 , wherein a corner between a top surface of the well and a well sidewall is characterized by a radius of curvature r less than 20 μm. 
     
     
         22 . The nanopore cell of  claim 14 , wherein a corner between a top surface of the well and a well sidewall is characterized by a radius of curvature r less than 3 μm.