Self-aligned well structures for low-noise chemical sensors

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.

What is claimed is: 
     
         1 . A chemical detection device, comprising:
 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; and   a fill material defining an reaction region extending above the sensing material, the reaction region overlying and substantially aligned with the floating gate conductor.   
     
     
         2 . The chemical detection device of  claim 1 , wherein the reaction region extends to the sensing material, and the reaction region is substantially aligned with the sensing material. 
     
     
         3 . The chemical detection device 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. 
     
     
         4 . The chemical detection device of  claim 1 , wherein the reaction region is self-aligned with the floating gate conductor. 
     
     
         5 . The chemical detection device of  claim 2 , wherein the chemically-sensitive field effect transistor generates a sensor signal in response to a chemical reaction occurring within the reaction region. 
     
     
         6 . The chemical detection device of  claim 5 , wherein the chemical reaction is a sequencing reaction. 
     
     
         7 . The chemical detection device of  claim 2 , wherein the sensing material comprises a metal-oxide. 
     
     
         8 . The chemical detection device of  claim 2 , wherein the sensing material is sensitive to hydrogen ions. 
     
     
         9 . The chemical detection device of  claim 2 , further comprising a microfluidic structure in fluid flow communication with the reaction region, and arranged to deliver analytes for sequencing.