Methods and apparatus for measuring analytes using large scale FET arrays
First Claim
1. A chemical detection device, comprising:
- an array of chemical detection pixels formed in columns and rows, each column including a plurality of chemical detection pixels, each pixel including;
a chemically-sensitive field effect transistor having a body terminal, a first terminal and a second terminal, the first terminal of the chemically-sensitive transistor coupled to a first readout signal line common to all chemical detection pixels of the column and the body terminal coupled to a body biasing voltage source line common to all pixels;
a first switch coupling the second terminal of the chemically-sensitive transistor to a current source; and
a second switch coupling the second terminal of the chemically-sensitive transistor to a second readout signal line common to all chemical detection pixels of the column; and
a plurality of readout circuits, each readout circuit corresponding to a column of chemical detection pixels of the array, each readout circuit including;
a first operational amplifier having a first input and a first output, the first input coupled to the second readout signal line common to all chemical detection pixels of a respective column;
a second operational amplifier having a second input and a second output, the second output coupled to the first readout signal line common to all chemical detection pixels of the respective column; and
a first transistor coupled between the first output and the second input.
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Abstract
Methods and apparatus relating to very large scale FET arrays for analyte measurements. ChemFET (e.g., ISFET) arrays may be fabricated using conventional CMOS processing techniques based on improved FET pixel and array designs that increase measurement sensitivity and accuracy, and at the same time facilitate significantly small pixel sizes and dense arrays. Improved array control techniques provide for rapid data acquisition from large and dense arrays. Such arrays may be employed to detect a presence and/or concentration changes of various analyte types in a wide variety of chemical and/or biological processes. In one example, chemFET arrays facilitate DNA sequencing techniques based on monitoring changes in hydrogen ion concentration (pH), changes in other analyte concentration, and/or binding events associated with chemical processes relating to DNA synthesis.
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Citations
25 Claims
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1. A chemical detection device, comprising:
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an array of chemical detection pixels formed in columns and rows, each column including a plurality of chemical detection pixels, each pixel including; a chemically-sensitive field effect transistor having a body terminal, a first terminal and a second terminal, the first terminal of the chemically-sensitive transistor coupled to a first readout signal line common to all chemical detection pixels of the column and the body terminal coupled to a body biasing voltage source line common to all pixels; a first switch coupling the second terminal of the chemically-sensitive transistor to a current source; and a second switch coupling the second terminal of the chemically-sensitive transistor to a second readout signal line common to all chemical detection pixels of the column; and a plurality of readout circuits, each readout circuit corresponding to a column of chemical detection pixels of the array, each readout circuit including; a first operational amplifier having a first input and a first output, the first input coupled to the second readout signal line common to all chemical detection pixels of a respective column; a second operational amplifier having a second input and a second output, the second output coupled to the first readout signal line common to all chemical detection pixels of the respective column; and a first transistor coupled between the first output and the second input. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A chemical detection device, comprising:
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a substrate of a first semiconductor type; an array of chemical detection pixels formed in columns and rows, each column including a plurality of chemical detection pixels in rows, each pixel including; a chemically-sensitive field effect transistor formed in the substrate, the chemically-sensitive field effect transistor having a body terminal coupled to a body biasing voltage source line common to all pixels; a first switch consisting of a first field effect transistor formed in the substrate; and a second switch consisting of a second field effect transistor formed in the substrate; and a plurality of readout circuits formed in the substrate, each readout circuit corresponding to a column of chemical detection pixels of the array. - View Dependent Claims (16, 17, 18)
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19. A method for calibrating a chemical detection device, comprising:
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placing a solution having a known pH level in proximity to a sensor array of the chemical detection device, the sensor array including a plurality of chemical detection pixels each having a chemically-sensitive field effect transistor; applying a body biasing voltage higher than ground to body terminals of the chemically-sensitive field effect transistors of each chemical detection pixel of the sensor array; and adjusting a reference electrode voltage applied to the chemical detection device until the array output signals provide pixel voltages at a desired reference level. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification