CHEMICALLY-SENSITIVE FIELD EFFECT TRANSISTOR BASED PIXEL ARRAY WITH PROTECTION DIODES

• US 20130001653A1
• Filed: 09/07/2012
• Published: 01/03/2013
• Est. Priority Date: 05/29/2009
• Status: Active Grant

• Current Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Milgrew, Mark, Bustillo, James, Rearick, Todd
• Granted Patent: US 8,994,076 B2
• Time in Patent Office: Days
• US Class Current: 257/253
• CPC Class Codes: C12Q 1/6869 Methods for sequencing
• CPC Class Codes: C12Q 1/6874 involving nucleic acid arrays, e.g. sequencing by hybridisation
• CPC Class Codes: G01N 27/27 Association of two or more measuring systems or cells, each measuring a different parameter, where the measurement results may be either used independently, the systems or cells being physically associated, or combined to produce a value for a further parameter
• 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
• CPC Class Codes: G01N 33/54373 involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

Methods and apparatus relating to FET arrays for monitoring chemical and/or biological reactions such as nucleic acid sequencing-by-synthesis reactions. Some methods provided herein relate to improving signal (and also signal to noise ratio) from released hydrogen ions during nucleic acid sequencing reactions.

Claims

1. A chemically-sensitive field effect transistor (chemFET), comprising:

a substrate including a semiconductor body;

a gate dielectric on the body;

a floating gate structure disposed over the gate dielectric;

a passivation layer over the floating gate structure; and

a diode connected between the floating gate and the semiconductor body.

2. The chemFET of claim 1, wherein the diode has a cathode connected to the semiconductor body, and the semiconductor body has n-type conductivity.

3. The chemFET of claim 1, wherein the semiconductor body is a well in a region of substrate having a conductivity type opposite that of the semiconductor body.

4. The chemFET of claim 3, including a second diode connected between the floating gate and the substrate.

5. The chemFET of claim 4, wherein the diode has a cathode connected to the semiconductor well, and the semiconductor well has n-type conductivity, and the second diode has an anode connected to the substrate.

6. The chemFET of claim 1, wherein the floating gate structure comprises a gate element on the gate dielectric, and a plurality of patterned conductors in respective patterned conductor layers connected together and to the gate element by interlayer connectors, the plurality of patterned conductors including a sensor plate.

7. The chemFET of claim 1, further comprising a source and a drain in the semiconductor body.

8. The chemFET of claim 1, further comprising a chemical sample well coupled to the passivation layer.

9. The chemFET of claim 1, wherein the chemFET produces an output indicating an ion-concentration in an analyte solution coupled to the floating gate via the passivation layer.

10. A chemically-sensitive field effect transistor (chemFET), comprising:

a semiconductor substrate including a well region of opposite conductivity type;

a gate dielectric on the well region;

a floating gate structure;

a passivation layer over the floating gate structure; and

a diode connected between the floating gate and the semiconductor substrate.

11. The chemFET of claim 10, wherein the semiconductor substrate has a conductivity type opposite that of the semiconductor body, and the semiconductor body comprises a well in the semiconductor substrate.

12. The chemFET of claim 10, wherein the diode has an anode connected to the semiconductor substrate, and the semiconductor substrate has p-type conductivity.

13. The chemFET of claim 10, wherein the floating gate structure comprises a gate element on the gate dielectric, and a plurality of patterned conductors in respective patterned conductor layers connected together and to the gate element by interlayer connectors, the plurality of conductors including a sensor plate.

14. The chemFET of claim 10, further comprising a source and a drain in the semiconductor body.

15. The chemFET of claim 10, further comprising a chemical sample well coupled to the passivation layer.

16. The chemFET of claim 10, wherein the chemFET produces an output indicating an ion-concentration in an analyte solution coupled to the floating gate via the passivation layer.

17. An apparatus, comprising:

an array of chemically-sensitive field effect transistors (chemFETs) on a substrate including a plurality of semiconductor body regions, a chemFET in the array disposed in one of the plurality of semiconductor body regions, and including a floating gate structure having a sensor plate, a passivation layer over the sensor plate, and a diode connected between the floating gate structure and the one of the plurality of semiconductor body regions.

18. The apparatus of claim 17, wherein the diode has a cathode connected to the one of the plurality of semiconductor body regions.

19. The apparatus of claim 17, wherein the substrate comprises a semiconductor having a conductivity type opposite that of the plurality of semiconductor body regions, and the plurality of semiconductor body regions comprise wells in the substrate.

20. The apparatus of claim 19, including a second diode connected between the floating gate and the substrate.

21. The apparatus of claim 20, wherein the diode has a cathode connected to the well forming the one of the plurality of semiconductor body regions, the well having an n-type conductivity, and the second diode has an anode connected to the substrate.

22. The apparatus of claim 17, wherein the floating gate structure in the chemFET comprises a gate element on the gate dielectric, and a plurality of patterned conductors in respective patterned conductor layers connected together and to the gate element by interlayer connectors, the plurality of patterned conductors including a sensor plate.

23. The apparatus of claim 17, the chemFET including a source and a drain in the semiconductor body.

24. The apparatus of claim 17, including an array of chemical sample wells coupled to the passivation layers of chemFETs in the array of chemFETs.

25. The apparatus of claim 17, wherein the chemFETs in the array produce outputs indicating an ion-concentration in an analyte solution coupled to the floating gate structures.

26. The apparatus of claim 25, further comprising circuitry coupled to the array to read the outputs of the chemFETs.