FEEDBACK CONTROL OF DIMENSIONS IN NANOPORE AND NANOFLUIDIC DEVICES

• US 20160355942A1
• Filed: 08/20/2016
• Published: 12/08/2016
• Est. Priority Date: 11/02/2010
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Harrer, Stefan, Rossnagel, Stephen M., Waggoner, Philip S.
• Granted Patent: US 10,316,423 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81C 1/00071 Channels
• CPC Class Codes: B81C 2201/0114 Electrochemical etching, anodic oxidation
• CPC Class Codes: C25D 9/06 by anodic processes

Abstract

Nanofluidic passages such as nanochannels and nanopores are closed or opened in a controlled manner through the use of a feedback system. An oxide layer is grown or removed within a passage in the presence of an electrolyte until the passage reaches selected dimensions or is closed. The change in dimensions of the nanofluidic passage is measured during fabrication. The ionic current level through the passage can be used to determine passage dimensions. Fluid flow through an array of fluidic elements can be controlled by selective oxidation of fluidic passages between elements.

Claims

1. A method comprising:

providing a substrate comprising a nanofluidic passage bounded by an electrical conductor;

filling the nanofluidic passage with an electrolyte; and

causing the nanofluidic passage to at least partially close by electrochemically oxidizing the electrical conductor.

2. The method of claim 1 further including setting a target dimension for the nanofluidic passage, monitoring the size of the nanofluidic passage by measuring ionic current through the nanofluidic passage, and discontinuing causing the nanofluidic passage to at least partially close when the target dimension is reached.

3. The method of claim 2 wherein the nanofluidic passage is a nanopore extending orthogonally to a surface of the substrate.

4. The method of claim 2 wherein the step of causing the nanofluidic passage to at least partially close includes applying an electric potential between the electrical conductor and the electrolyte.

6. The method of claim 1 wherein the substrate comprises a membrane including a large plurality of nanofluidic passages extending therethrough, each of the nanofluidic passages being bounded by the electrical conductor, and further wherein the electrical conductor comprises a metal or metal alloy coating each nanofluidic passage.

20. The method of claim 2, further including the step of reversing the step of electrochemically oxidizing the electrical conductor, thereby enlarging the dimensions of the nanofluidic passage.

5. (canceled)

7-8. -8. (canceled)

9. A method comprising:

forming a nanofluidic passage having larger than targeted dimensions in a substrate;

forming an electrically conductive layer on the substrate, thereby reducing the dimensions of the nanofluidic passage,

filling the nanofluidic passage with an electrolyte; and

electrochemically oxidizing the electrically conductive layer to further reduce the dimensions of the nanofluidic passage until the fluidic passage has the targeted dimensions.

10. The method of claim 9 wherein the step of electrochemically oxidizing the conductive layer includes applying an electric potential between the electrolyte and the conductive layer.

11. The method of claim 10 further including the steps of monitoring ionic current through the nanofluidic passage and discontinuing the step of electrochemically oxidizing the electrically conductive layer when the ionic current reaches a level representative of the targeted dimensions.

12. The method of claim 9 wherein the step of forming the nanofluidic passage includes obtaining a substrate including a base, a first layer on the base, and a second layer on the first layer, forming a nanopore in the second layer, etching the first layer through the nanopore and beneath the second layer to form a reservoir within the first layer having a width greater than a width of the nanopore, the step of forming the electrically conductive layer further including coating surfaces of the reservoir and nanopore with a metal or metal alloy, and further including the step of monitoring the dimensions of the nanopore during the electrochemical oxidation of the electrically conductive layer using ionic current measurements.

13. The method of claim 9 wherein the nanofluidic passage is a nanopore extending orthogonally with respect to a surface of the substrate.

16. The method of claim 9 wherein the electrically conductive layer is selected from the group consisting of titanium, tungsten, and tantalum.

14-15. -15. (canceled)

17-19. -19. (canceled)