FEEDBACK CONTROL OF DIMENSIONS IN NANOPORE AND NANOFLUIDIC DEVICES

• US 20120103821A1
• Filed: 02/04/2011
• Published: 05/03/2012
• 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 9,422,154 B2
• Time in Patent Office: Days
• US Class Current: 205/84
• 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 forming an oxide layer on the conductor.

2. The method of claim 1 further including setting a target dimension for the nanofluidic passage, monitoring the size of 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.

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 conductor and the electrolyte.

5. The method of claim 2 wherein the nanofluidic passage is a surface channel in the substrate.

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 conductor, further comprising the step of causing the nanofluidic passages to at least partially close by electrochemically forming an oxide on the conductor.

7. A method comprising:

providing an array of fluidic elements, each of the fluidic elements being connected to one or more other fluidic elements in the array by one or more nanofluidic passages, each of the nanofluidic passages including an electrically conductive surface, and

selectively closing one or more of the nanofluidic passages by causing an oxidized layer to electrochemically grow on the electrically conductive surface in selected nanofluidic passages.

8. The method of claim 7 wherein each of the nanofluidic passages includes an electrolyte therein, the step of selectively closing including applying an electric potential between the electrically conductive surface and the electrolyte.

9. A method comprising:

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

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

filling the nanofluidic passage with an electrolyte; and

electrochemically oxidizing the conductive layer 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 step of monitoring ionic current through the nanofluidic passage.

12. The method of claim 9 further including the step of monitoring ionic current through the nanofluidic passage.

13. The method of claim 9 wherein the nanofluidic passage is a nanopore.

14. The method of claim 9 wherein the nanofluidic passage is a channel.

15. The method of claim 14 wherein the channel is formed with an opening in a surface of the substrate, further including the step of closing the opening when forming the conductive layer on the substrate.

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

17. A computer program product for controlling the fabrication of a nanofluidic device including a nanofluidic passage in a substrate, the nanofluidic passage comprising an electrically conductive surface and containing an electrolyte:

a computer readable storage medium having computer readable program code embodied therewith, said computer readable program code comprising;

computer readable program code configured to facilitate applying an electric potential between the electrolyte and the electrically conductive surface sufficient to cause oxidation of the electrically conductive surface;

computer readable program code configured to monitor ionic current through the nanofluidic passage.

18. The computer program product of claim 17, further comprising computer readable program code configured to continuously monitor ionic current as the conductive surface is oxidized.

19. The computer program product of claim 17, further comprising computer readable program code configured to alternatively monitor the ionic current and apply the electric potential between the electrolyte and the conductive surface until a desired nanofluidic passage size is reached.

20. A method comprising:

providing a nanofluidic device including a nanofluidic passage having an electrically conductive surface and an electrolyte within the nanofluidic passage; and

applying a voltage to the electrically conductive surface to electrochemically change the dimensions of the nanofluidic passage.

21. The method of claim 20 further including reducing the dimensions of the nanofluidic passage by oxidizing the electrically conductive surface.

22. The method of claim 20 further including increasing the dimensions of the nanofluidic passage by reducing the thickness of the electrically conductive surface.

23. The method of claim 20 further comprising the steps of causing an ionic current to flow through the nanofluidic passage and monitoring the ionic current.

24. The method of claim 20 wherein the nanofluidic device includes a nanofilter membrane having a large plurality of nanofluidic passages, further including the step of electrochemically changing the dimensions of the nanofluidic passages within the membrane.

25. The method of claim 24 further including monitoring an ionic current through the nanofilter membrane.