CHEMICAL DEVICE WITH THIN CONDUCTIVE ELEMENT
In one implementation, a chemical device is described. The sensor includes a chemically-sensitive field effect transistor including a floating gate structure having a plurality of floating gate conductors electrically coupled to one another. A conductive element overlies and is in communication with an uppermost floating gate conductor in the plurality of floating gate conductors. The conductive element is wider and thinner than the uppermost floating gate conductor. A dielectric material defines an opening extending to an upper surface of the conductive element.
1 . A chemical device, comprising:
a chemically-sensitive field effect transistor including a floating gate structure comprising a plurality of floating gate conductors electrically coupled to one another;
a conductive element overlying and in communication with an uppermost floating gate conductor in the plurality of floating gate conductors, the conductive element wider and thinner than the uppermost floating gate conductor; and
a dielectric material defining an opening extending to an upper surface of the conductive element.
2 . The chemical device of claim 1 , wherein the conductive element comprises at least one of titanium, tantalum, titanium nitrite, and aluminum, and/or oxides and/or mixtures thereof.
3 . The chemical device of claim 1 , wherein the distance between adjacent conductive elements in the chemical device is about 0.18 microns.
4 . The chemical device of claim 1 , wherein the thickness of the conductive element is about 0.1-0.2 microns.
5 . The chemical device of claim 1 , wherein the uppermost floating gate conductor in the plurality of floating gate conductors has a thickness greater than a thickness of other floating gate conductors in the plurality of floating gate conductors.
6 . The chemical device of claim 1 , wherein the conductive element comprises a material different from a material comprising the uppermost floating gate conductor.
7 . The chemical device of claim 1 , wherein an inner surface of the dielectric material and the upper surface of the conductive element define an outer surface of a reaction region for the chemical device.
8 . The chemical device of claim 1 , wherein the plurality of floating gate conductors is within a layer that includes array lines and bus lines.
9 . The chemical device of claim 1 , including a sensor region containing the chemically-sensitive field effect transistor and a peripheral region containing peripheral circuitry to obtain a signal from the chemically-sensitive field effect transistor.
10 . The chemical device of claim 9 , wherein the conductive element is within a conductive layer that is only within the sensor region.
11 . The chemical device of claim 9 , wherein the conductive element comprises a material not within the peripheral region.
12 . The chemical 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.
13 . The chemical device of claim 1 , wherein a first layer of the dielectric material is silicon nitride and a second layer is at least one of silicon dioxide and tetraethyl orthosilicate, and the second layer defines sidewalls of the opening.
14 . The chemical device 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.
15 . A method for manufacturing a chemical device, the method comprising:
forming a chemically-sensitive field effect transistor including a floating gate structure comprising a plurality of floating gate conductors electrically coupled to one another;
forming a conductive element overlying and in communication with an uppermost floating gate conductor in the plurality of floating gate conductors, the conductive element wider and thinner than the uppermost floating gate conductor; and
forming a dielectric material defining an opening extending to an upper surface of the conductive element.
16 . The method for manufacturing a chemical device of claim 15 , wherein the upper surface of the conductive element defines a bottom surface of a reaction region for the chemical device.
17 . The method for manufacturing a chemical device of claim 15 , wherein an inner surface of the dielectric material and the upper surface of the conductive element define an outer boundary of a reaction region for the chemical device.
18 . The method for manufacturing a chemical device of claim 15 , wherein the conductive element is formed within a conductive layer that is only within a sensor region of the chemical device.