ONE-TRANSISTOR PIXEL ARRAY

• US 20120056248A1
• Filed: 06/30/2011
• Published: 03/08/2012
• Est. Priority Date: 06/30/2010
• Status: Active Grant

• Current Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: FIFE, Keith
• Granted Patent: US 8,415,176 B2
• Time in Patent Office: Days
• US Class Current: 257/253
• CPC Class Codes: C12Q 1/6869 Methods for sequencing
• CPC Class Codes: G01J 1/46 using a capacitor
• CPC Class Codes: G01N 27/4143 Air gap between gate and channel, i.e. suspended gate [SG] FETs work function measurement per se G01N27/002
• 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 33/00 Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
• CPC Class Codes: G01R 29/26 Measuring noise figure; Measuring signal-to-noise ratio
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 29/66 Types of semiconductor device ; Multistep manufacturing processes therefor
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: Y10T 436/25875 Gaseous sample or with change of physical state

Abstract

To reduce the pixel size to the smallest dimensions and simplest form of operation, a pixel may be formed by using only one ion sensitive field-effect transistor (ISFET). This one-transistor, or 1T, pixel can provide gain by converting the drain current to voltage in the column. Configurable pixels can be created to allow both common source read out as well as source follower read out. A plurality of the 1T pixels may form an array, having a number of rows and a number of columns and a column readout circuit in each column.

Claims

1. A chemical detection pixel, comprising:

one and only one transistor, said transistor being a chemically-sensitive transistor (ChemFET);

one and only one row line; and

one and only one column line.

2. The chemical detection pixel of claim 1, wherein the chemically-sensitive transistor is a field effect transistor having a floating gate.

3. The chemical detection pixel of claim 2, wherein the drain of the chemically-sensitive field effect transistor is coupled to the row line, and the source of the chemically-sensitive transistor is coupled to the column line.

4. The chemical detection pixel of claim 2, wherein the drain of the ChemFET is coupled to the column line, and the source of the ChemFET is coupled to the row line.

5. The chemical detection pixel of claim 2, wherein the ChemFET is configured in a source follower mode, with the drain of the ChemFET coupled to a fixed voltage and the source of the ChemFET grounded via a current source, and wherein the source of the ChemFET is coupled to an output line.

6. The chemical detection pixel of claim 5, wherein the output line is a readout line.

7. The chemical detection pixel of claim 2, wherein the ChemFET is configured in a common source mode, with the drain of the ChemFET coupled to a fixed voltage via a current source and the source of the ChemFET coupled to a second fixed voltage, and wherein the drain of the ChemFET is coupled to an output line.

8. The chemical detection pixel of claim 7, wherein the output line is a readout line.

9. The chemical detection pixel of claim 1, wherein the chemically-sensitive transistor is an N-channel Metal Oxide-Semiconductor (NMOS) device.

10. The chemical detection pixel of claim 1, wherein the chemically-sensitive transistor is a P-channel Metal-Oxide-Semiconductor (PMOS).

11. The chemical detection pixel of claim 1, wherein the chemically-sensitive transistor is configured to operate in a subthreshold region of operation.

12. The chemical detection pixel of claim 11, wherein the subthreshold region of operation has a transconductance slope of approximately 100 mV/decade.

13. The chemical detection pixel of claim 1, wherein the ChemFET is an ion sensitive field effect transistor.

14. The chemical detection pixel of claim 2, wherein the ChemFET is an N-channel field effect transistor.

15. The chemical detection pixel of claim 2, wherein the ChemFET is a P-channel field effect transistor.

16. A chemical detection pixel array, comprising:

a plurality of chemically-sensitive pixels, each pixel comprising;

one and only one transistor, said transistor being a chemically-sensitive transistor (ChemFET);

one and only one row line; and

one and only one column line; and

a readout switch,

wherein the ChemFET is a field effect transistor having a floating gate, and wherein the drain of the ChemFET is coupled to the row line, and the source of the ChemFET is coupled to the column line.

17. The chemical detection pixel array of claim 16, wherein the readout switch is a column readout switch.

18. The chemical detection pixel array of claim 17, wherein the column readout switch comprises a first switch for grounding a column of pixels in the array.

19. The chemical detection pixel array of claim 17, wherein the column readout switch includes a first switch for precharging a column of pixels in the array to a reference voltage.

20. The chemical detection pixel array of claim 18, wherein the column readout switch includes a second switch, and the readout value on the column is determined when the second switch is open.

21. The chemical detection pixel array of claim 17, wherein the column readout switch is at an end of a column line.

22. A chemical detection pixel array, comprising:

a plurality of chemically-sensitive pixels, each pixel comprising;

one and only one transistor, said transistor being a chemically-sensitive transistor (ChemFET);

one and only one row line; and

one and only one column line; and

a readout switch,

wherein the ChemFET is a field effect transistor having a floating gate, and wherein the drain of the ChemFET is coupled to the column line, and the source of the ChemFET is coupled to the row line.

23. The chemical detection pixel array of claim 22, wherein the readout switch is a column readout switch.

24. The chemical detection pixel array of claim 22, wherein the column readout switch comprises a first switch for grounding a column of pixels in the array.

25. The chemical detection pixel array of claim 22, wherein the column readout switch has a first switch for precharging a column of pixels in the array to a reference voltage.

26. The chemical detection pixel array of claim 22, wherein the column readout switch comprises a second switch, and the value on the column is determined when the second switch is open.

27. The chemical detection pixel array of claim 22, wherein the column readout switch is at an end of a column line.

28. The chemical detection pixel array of claim 22, wherein a readout value on the column line is determined almost entirely by the ChemFET corresponding to an active row.

29. The chemical detection pixel array of claim 22, wherein a row line is configured to operate with an active low signal when the row is selected for a readout mode of operation.

30. The chemical detection pixel array of claim 22, wherein the plurality of ChemFETs comprise multiple pairs of ChemFETs, and each pair share a common drain.

31. The chemical detection pixel array of claim 22, wherein the plurality of ChemFETs comprise multiple pairs of ChemFETs, and each pair share a common source.

32. The chemical detection pixel array of claim 22, wherein the source and drain regions make use of a shared diffusion, shared contact and shared via to a column line.