Chemical sensor with protruded sensor surface

• US 8,841,217 B1
• Filed: 03/13/2013
• Issued: 09/23/2014
• 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, Bustillo, James, Owens, Jordan
• Primary Examiner(s): Nhu, David
• Application Number:
  US13/801,243
• Publication Number:
  US 20140264466A1
• Time in Patent Office: 559 Days
• Field of Search: 438/700, 438/270, 438/706, 438/712, 438/745, 438/679, 438/513, 438/733, 438/197, 438/194, 438/174, 257/288, 257/277, 257/315, 257/E21.006, 257/E21.027, 257/E21.051, 257/E21.058, 257/E21.062, 257/E21.17, 257/E21.2, 257/E21.212, 257/E21.245, 257/E21.229, 257/E21.267, 257/E21.319, 257/E21.332
• US Class Current: 438/700
• CPC Class Codes: G01N 27/414 Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS

Abstract

In one implementation, a chemical sensor is described. The chemical sensor includes a 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 element on a sidewall of the opening and extending over an upper surface of the dielectric material.

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;

a conductive element on a sidewall of the opening and extending over an upper surface of the dielectric material, 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.

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

3. The chemical sensor of claim 1, wherein the conductive element extends across the upper surface of the floating gate conductor to define a bottom surface of a reaction region for the chemical sensor.

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

5. The chemical sensor of claim 1, further comprising a layer of sensing material on the conductive element.

6. The chemical sensor of claim 5, wherein the sensing material comprises a metal-oxide.

7. The chemical sensor of claim 1, wherein a sensing surface for the chemical sensor includes an inner surface of the conductive element.

8. The chemical sensor of claim 7, wherein the sensing surface is sensitive to hydrogen ions.

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 element.

10. 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;

a conductive element on a sidewall of the opening and extending over an upper surface of the dielectric material, wherein the conductive element does not extend into a second opening of an adjacent chemically-sensitive field effect transistor.

11. 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 element on a sidewall of the opening and extending over an upper surface of the dielectric material, wherein forming the conductive element includes

depositing a conductive material within the opening and on the upper surface of the dielectric material,

forming a mask element within the opening and over at least a portion of the upper surface of the dielectric material, and

etching the conductive material using the mask element as an etch mask, thereby forming the conductive element.

12. The method of claim 11, wherein forming the mask element comprises performing a lithographic process.

13. The method of claim 11, wherein:

forming the mask element exposes conductive material on a second portion of the upper surface of the dielectric material; and

etching the conductive material removes the exposed conductive material.

14. The method of claim 11, wherein the conductive element includes an inner surface defining a reaction region for the chemical sensor.

15. The method of claim 11, wherein forming the conductive element includes forming the conductive element on the upper surface of the floating gate conductor to define a bottom surface of a reaction region for the chemical sensor.

16. The method of claim 11, wherein the conductive element comprises an electrically conductive material, and an inner surface of the conductive element includes an oxide of the electrically conductive material.

17. The method of claim 11, further comprising forming a layer of sensing material on the conductive element.

18. The method of claim 11, wherein a sensing surface for the chemical sensor includes an inner surface of the conductive element.