CHEMICAL SENSOR WITH SIDEWALL SPACER SENSOR SURFACE

• US 20140264464A1
• Filed: 03/13/2013
• Published: 09/18/2014
• Est. Priority Date: 03/13/2013
• Status: Active Grant

• Current Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: FIFE, Keith G., BUSTILLO, James, OWENS, Jordan
• Granted Patent: US 8,963,216 B2
• Time in Patent Office: Days
• US Class Current: 257/253
• CPC Class Codes: G01N 27/414 Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS
• CPC Class Codes: G01N 27/4145 specially adapted for biomolecules, e.g. gate electrode with immobilised receptors

Abstract

In one implementation, a chemical sensor is described. The chemical sensor includes chemically-sensitive field effect transistor including a floating gate conductor having an upper surface. A dielectric material defines an opening extending to the upper surface of the floating gate conductor. A conductive sidewall spacer is on a sidewall of the opening and contacts the upper surface of the floating gate conductor.

Claims

1. A chemical sensor comprising:

a chemically-sensitive field effect transistor including a floating gate conductor having an upper surface;

a dielectric material defining an opening extending to the upper surface of the floating gate conductor; and

a conductive sidewall spacer on a sidewall of the opening and contacting the upper surface of the floating gate conductor.

2. The chemical sensor of claim 1, wherein the conductive sidewall spacer includes an inner surface surrounding a reaction region for the chemical sensor.

3. The chemical sensor of claim 2, wherein the inner surface of the conductive sidewall spacer is an outer surface of the reaction region, and the upper surface of the floating gate conductor is a bottom surface of the reaction region.

4. The chemical sensor of claim 1, wherein the conductive sidewall spacer comprises an electrically conductive material, and an inner surface of the conductive sidewall spacer includes an oxide of the electrically conductive material.

5. The chemical sensor of claim 1, wherein a sensing surface for the chemical sensor includes an inner surface of the conductive sidewall spacer and the upper surface of the floating gate conductor.

6. The chemical sensor of claim 5, wherein the sensing surface is sensitive to hydrogen ions.

7. The chemical sensor of claim 1, wherein the conductive sidewall spacer comprises material different from material at the upper surface of the floating gate conductor.

8. The chemical sensor of claim 1, wherein the chemically-sensitive field effect transistor includes a floating gate structure comprising a plurality of conductors electrically coupled to one another and separated by dielectric layers, and the floating gate conductor is an uppermost conductor in the plurality of conductors.

9. The chemical sensor of claim 1, wherein the chemically-sensitive field effect transistor generates a sensor signal in response to a chemical reaction occurring proximate to the conductive sidewall spacer.

10. The chemical sensor of claim 9, wherein the chemical reaction is a sequencing reaction.

11. The chemical sensor of claim 1, further comprising a microfluidic structure in fluid flow communication with the chemically-sensitive field effect transistor, and arranged to deliver analytes for sequencing.

12. A method for manufacturing a chemical sensor, the method comprising:

forming a chemically-sensitive field effect transistor including a floating gate conductor having an upper surface;

forming a dielectric material defining an opening extending to the upper surface of the floating gate conductor; and

forming a conductive sidewall spacer on a sidewall of the opening and contacting the floating gate conductor.

13. The method of claim 12, wherein forming the conductive sidewall spacer comprises:

depositing a conductive material within the opening;

etching the conductive material to expose the upper surface of the floating gate conductor.

14. The method of claim 12, wherein:

depositing the conductive material includes depositing the conductive material on an upper surface of the dielectric material; and

etching the conductive material exposes the upper surface of the dielectric material.

15. The method of claim 12, wherein the conductive sidewall spacer includes an inner surface surrounding a reaction region for the chemical sensor.

16. The method of claim 15, wherein the inner surface of the conductive sidewall spacer is an outer surface of the reaction region, and the upper surface of the floating gate conductor is a bottom surface of the reaction region.

17. The method of claim 12, wherein the conductive sidewall spacer comprises an electrically conductive material, and an inner surface of the conductive sidewall spacer includes an oxide of the electrically conductive material.

18. The method of claim 12, wherein a sensing surface for the chemical sensor includes an inner surface of the conductive sidewall spacer and the upper surface of the floating gate conductor.

19. The method of claim 18, wherein the sensing surface is sensitive to hydrogen ions.

20. The method of claim 12, wherein the conductive sidewall spacer comprises material different from material at the upper surface of the floating gate conductor.