Differential sensing with biofet sensors
A sensor array includes a semiconductor substrate, a first plurality of FET sensors and a second plurality of FET sensors. Each of the FET sensors includes a channel region between a source and a drain region in the semiconductor substrate and underlying a gate structure disposed on a first side of the channel region, and a dielectric layer disposed on a second side of the channel region opposite from the first side of the channel region. A first plurality of capture reagents is coupled to the dielectric layer over the channel region of the first plurality of FET sensors, and a second plurality of capture reagents is coupled to the dielectric layer over the channel region of the second plurality of FET sensors. The second plurality of capture reagents is different from the first plurality of capture reagents.
1. A sensor, comprising:
a substrate;
a first field effect transistor (FET) sensor, comprising:
a first gate structure disposed on a first side of the substrate,
a first dielectric layer disposed on a second side of the substrate, and
a first capture reagent coupled to the first dielectric layer; and
a second FET sensor, comprising:
a second gate structure disposed on the first side of the substrate,
a second dielectric layer disposed on the second side of the substrate, and
a second capture reagent coupled to the second dielectric layer, wherein the second capture reagent is different from the first capture reagent and wherein the first and second FET sensors are coupled to a common reference electrode.
2. The sensor of claim 1 , wherein the first and second dielectric layers are different regions of a dielectric layer.
3. The sensor of claim 1 , wherein the first and second dielectric layers comprise materials different from each other.
4. The sensor of claim 1 , wherein the first and second dielectric layers comprise high-k dielectric materials.
5. The sensor of claim 1 , wherein the first FET sensor further comprises a first well disposed on the second side of the substrate and the first dielectric layer is disposed in the first well; and
wherein the second FET sensor further comprises a second well disposed on the second side of the substrate and the second dielectric layer is disposed in the second well.
6. The sensor of claim 5 , wherein the first and second wells are separated from each other by a distance of about 1 μm to about 1 mm.
7. The sensor of claim 1 , wherein the first FET sensor further comprises a first channel region between the first gate structure and the first dielectric layer; and
wherein the second FET sensor further comprises a second channel region between the second gate structure and the second dielectric layer.
8. The sensor of claim 1 , wherein the first FET sensor is configured to detect a first type of analyte and the second FET sensor is configured to detect a second type of analyte that is different from the first type of analyte.
9. The sensor of claim 1 , further comprising an insulating layer disposed on the second side of the substrate.
10. The sensor of claim 9 , wherein the insulating layer comprises first and second openings, and
wherein the first and second dielectric layers are disposed in the first and second openings, respectively.
11. A sensor, comprising:
a substrate;
an array of channel regions disposed in the substrate and arranged in a two-dimensional array;
an array of gate structures disposed on first sides of the channel regions and coupled to a common reference electrode; and
an array of dielectric layers disposed on second sides of the channel regions,
wherein a first set of dielectric layers in the array of dielectric layers is coupled to first capture reagents, and
wherein a second set of dielectric layers in the array of dielectric layers is free of capture reagents.
12. The sensor of claim 11 , wherein the array of dielectric layers are different regions of a dielectric layer.
13. The sensor of claim 11 , wherein the first and second sets of dielectric layers comprise materials different from each other.
14. The sensor of claim 11 , wherein a third set of dielectric layers in the array of dielectric layers is coupled to second capture reagents different from the first capture reagents.
15. The sensor of claim 11 , further comprising an insulating layer disposed on the substrate, wherein the insulating layer comprises an array of openings on the channel regions and wherein the array of dielectric layers are disposed in the openings.
16. The sensor of claim 15 , wherein each of the openings has an area between about 500 nm×500 nm and about 500 μm×500 μm.
17. A sensor, comprising:
a substrate;
an array of field effect transistors (FETs) comprising channel regions disposed in a substrate and gate structures disposed on first sides of the channel regions;
an insulating layer disposed on the substrate, wherein the insulating layer comprises openings aligned with second sides of the channel regions;
a dielectric layer disposed on the insulating layer and in the openings of the insulating layer;
first capture reagents coupled to first portions of the dielectric layer on the channel regions of a first set of FETs in the array of FETs; and
second capture reagents coupled to second portions of the dielectric layer on the channel regions of a second set of FETs in the array of FETs, wherein the first and second capture reagents are different from each other.
18. The sensor of claim 17 , wherein the array of FETs are coupled to a common reference electrode.
19. The sensor of claim 17 , wherein the dielectric layer comprises a high-k dielectric material.
20. The sensor of claim 17 , wherein the dielectric layer is in contact with the second sides of the channel regions.