Self-aligned well structures for low-noise chemical sensors

• US 8,962,366 B2
• Filed: 01/28/2013
• Issued: 02/24/2015
• Est. Priority Date: 01/28/2013
• Status: Active Grant

• Current Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Li, Shifeng, Putnam, Jonathan
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): ENAD, CHRISTINE A
• Application Number:
  US13/751,575
• Publication Number:
  US 20140209982A1
• Time in Patent Office: 757 Days
• Field of Search: 257/253, 438/49
• US Class Current: 438/49
• 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
• CPC Class Codes: G01N 27/4148 Integrated circuits therefor, e.g. fabricated by CMOS processing CMOS processing per se H01L21/82

Abstract

In one implementation, a chemical detection device is described. The device includes a chemically-sensitive field effect transistor including a floating gate conductor coupled to a gate dielectric and having an upper surface, and a sensing material on the upper surface. The device also includes a fill material defining a reaction region extending above the sensing material, the reaction region overlying and substantially aligned with the floating gate conductor.

Claims

1. A method for forming a chemical detection device, the method comprising:

forming a gate dielectric on a semiconductor substrate;

forming a floating gate structure on the gate dielectric, including;

forming a conductive material overlying the gate dielectric;

forming a sensing material on the conductive material;

forming a sacrificial material overlying the sensing material;

patterning the conductive material, the sensing material and the sacrificial material;

forming a fill material adjacent to the patterned sacrificial material and the patterned sensing material and the patterned conductive material; and

removing the patterned sacrificial material to expose the patterned sensing material and define a reaction region substantially aligned with the patterned conductive material.

2. The method of claim 1, wherein removing the patterned sacrificial material comprises using a non-etching process.

3. The method of claim 1, wherein removing the patterned sacrificial material comprises applying heat to thermally decompose at least some of the patterned sacrificial material.

4. The method of claim 3, wherein the fill material has a decomposition temperature greater than that of the sacrificial material.

5. The method of claim 1, wherein the sensing material comprises a metal-oxide.

6. The method of claim 1, wherein the sensing material is sensitive to hydrogen ions.

7. The method of claim 1, wherein the chemical detection device generates a sensor signal in response to a chemical reaction occurring within the reaction region.

8. The method of claim 7, wherein the chemical reaction is a sequencing reaction.

9. The method of claim 1, further comprising forming a source and drain in the semiconductor substrate.

10. The method of claim 1, wherein the reaction region is configured to receive at least one reactant.

11. The method of claim 1, wherein removing the patterned sacrificial material comprises using a wet etch process.