Fet type sensor, ion density detecting method comprising this sensor, and base sequence detecting method
First Claim
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1. An FET type sensor comprising;
- an input diode section and a floating diffusion section consisting of a diffusion region reverse to the substrate in conductivity type, formed across a specified interval on the face side of a P type or N type semiconductor substrate, an input gate and an output gate fixed by way of an insulation film, at positions on the substrate surface corresponding to the initial end and terminal end of a conductive channel formed from the input diode section to the floating diffusion section, a sensing section consisting of an ion sensitive film fixed by way of an insulation film, at a position on the substrate surface corresponding to the middle of the channel, a reset gate fixed by way of an insulation film, at a position on the substrate surface continuous to the side remote from the channel in the floating diffusion section, and a reset diode section consisting of a diffusion region reverse to the substrate in conductivity type, formed on the substrate surface at a side remote from the floating diffusion section in the reset gate, wherein a substance reacting or binding with a specimen in the sample in the sensing section or acting as catalyst for reaction of the specimen is fixed in the sensing section, and the electric charge accumulated in the floating diffusion section after resetting of the potential is detected as potential change, depending on the depth of the potential well changed according to the ion density acting on the sensing section and the number of times of seepage from the potential well.
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Abstract
The surface of a semiconductor substrate (1) comprises an input diode section (2) and a floating diffusion section (3) consisting of a diffusion region reverse to the substrate in conductivity type, an input gate (6) and an output gate (7) fixed on an insulation film (5) extending from an input diode section to a floating diffusion section, a sensing section (9) consisting of an ion sensitive film fixed on the insulation film extending from the input.
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Citations
16 Claims
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1. An FET type sensor comprising;
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an input diode section and a floating diffusion section consisting of a diffusion region reverse to the substrate in conductivity type, formed across a specified interval on the face side of a P type or N type semiconductor substrate, an input gate and an output gate fixed by way of an insulation film, at positions on the substrate surface corresponding to the initial end and terminal end of a conductive channel formed from the input diode section to the floating diffusion section, a sensing section consisting of an ion sensitive film fixed by way of an insulation film, at a position on the substrate surface corresponding to the middle of the channel, a reset gate fixed by way of an insulation film, at a position on the substrate surface continuous to the side remote from the channel in the floating diffusion section, and a reset diode section consisting of a diffusion region reverse to the substrate in conductivity type, formed on the substrate surface at a side remote from the floating diffusion section in the reset gate, wherein a substance reacting or binding with a specimen in the sample in the sensing section or acting as catalyst for reaction of the specimen is fixed in the sensing section, and the electric charge accumulated in the floating diffusion section after resetting of the potential is detected as potential change, depending on the depth of the potential well changed according to the ion density acting on the sensing section and the number of times of seepage from the potential well. - View Dependent Claims (2)
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3. (Cancelled).
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4. An FET type sensor comprising;
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an input diode section and a floating diffusion section consisting of a diffusion region reverse to the substrate in conductivity type, formed across a specified interval on the face side of a P type or N type semiconductor substrate, an input gate and an output gate fixed by way of an insulation film, at positions on the substrate surface corresponding to the middle and terminal end of a conductive channel formed from the input diode section to the floating diffusion section, a sensing section consisting of an ion sensitive film fixed by way of an insulation film, at a position on the substrate surface corresponding to the input end of the channel, a reset gate fixed by way of an insulation film, at a position on the substrate surface continuous to the side remote from the channel in the floating diffusion section, and a reset diode section consisting of a diffusion region reverse to the substrate in conductivity type, formed on the substrate surface at a side remote from the floating diffusion section in the reset gate, wherein it is designed to detect the electric charge accumulated in the floating diffusion section after resetting of the potential as potential change, depending on the depth of the potential well changed according to the ion density acting on the sensing section and the number of times of seepage from the potential well. - View Dependent Claims (5, 6, 7)
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8. An FET type sensor comprising an input diode section and a floating diffusion section consisting of a diffusion region reverse to the substrate in conductivity type, formed across a specified interval on the face side of a P type or N type semiconductor substrate wherein said floating diffusion section is divided into a first drain and a second drain, the input diode section is used as a common source having a portion corresponding to these two divisions, and first and second mutually parallel channels are formed in the substrate surface side between the source and drain,
a common reset diode consisting of a diffusion region reverse to the substrate in conductivity type is formed on the side of the floating diffusion section for composing the first and second drains, at the opposite side to the two channels, across a small interval from said floating diffusion section, and a common reset gate is fixed by way of an insulation film on the substrate surface in this small interval, an input gate and an output gate are fixed by way of an insulation film, at positions on the substrate surface corresponding to the both ends of the first channel, and a sensing section consisting of an ion sensitive film is fixed by way of an insulation film, at a position on the substrate surface corresponding to the middle of the first channel, an input gate and an output gate are fixed by way of an insulation film, at positions on the substrate surface corresponding to the middle and terminal end of the second channel, and a sensing section consisting of an ion sensitive film is fixed by way of an insulation film, at a position on the substrate surface corresponding to the initial end of the second channel, and it is designed to detect the electric charge accumulated in the first and second drains of the floating diffusion section after resetting of the potential as potential change, depending on the depth of the potential well changed according to the ion density acting on each sensing section on the first channel and second channel and the number of times of seepage from the potential well.
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10. (Cancelled).
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11. A detecting method of base sequence by using an FET type sensor comprising an input diode section and a floating diffusion section consisting of a diffusion region reverse to the substrate in conductivity type, formed across a specified interval on semiconductor substrate, a sensing section having a gold film exposed on the surface and fixed by way of an insulation film, at a position on the substrate surface corresponding to the middle or initial end of a conductive channel to be formed on the substrate surface layer in the interval, wherein a potential well varying in the depth according to the ion density acting on the sensing section is formed in the middle of the conductive channel, and the electric charge according to the seepage amount from the potential well is measured in the floating diffusion section,
at least one comparing electrode is fixed by way of an insulation film on the substrate surface near the sensing section, a terminal radical of single-strand nucleic acid complementary to a DNA specimen is fixed in the gold film, a same sample solution is supported in a region including the sensing section and comparing electrode, and the seepage electric charge amount from the potential well is measured on the basis of the potential of the comparing electrode, thereby detecting presence or absence of hybridization of the single-strand nucleic acid and specimen.
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12. A detecting method of base sequence by using an FET type sensor comprising an input diode section and a floating diffusion section consisting of a diffusion region reverse to the substrate in conductivity type, formed across a specified interval on semiconductor substrate, a sensing section having a gold film exposed on the surface and fixed by way of an insulation film, at a position on the substrate surface corresponding to the middle or initial end of a conductive channel to be formed on the substrate surface layer in the interval, wherein a potential well varying in the depth according to the ion density acting on the sensing section is formed in the middle of the conductive channel, and the electric charge according to the seepage amount from the potential well is measured in the floating diffusion section,
a terminal radical of single-strand nucleic acid complementary to a DNA specimen is fixed in the gold film, a sample solution is supported in the sensing section, a measuring electrode positioned directly above the gold film, and a comparing electrode disposed by deviating a distance slightly so as not to affect electrically the nucleic acid fixed on the gold film are provided above the sensing section, these two electrode are lowered to immerse in the sample solution, a potential enough to adsorb the DNA terminal radical hybridized on the nucleic acid fixed on the gold film by the measuring electrode is applied to these two electrodes, a current flowing between the measuring electrode and the grounding potential is measured on the basis of the current flowing in the comparing electrode, and presence or absence of hybridization between the single-strand nucleic acid and specimen is detected.
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13. A detecting method of base sequence by using an FET type sensor comprising an input diode section and a floating diffusion section consisting of a diffusion region reverse to the substrate in conductivity type, formed across a specified interval on semiconductor substrate, a sensing section consisting of an ion sensitive film fixed by way of an insulation film, at a position on the substrate surface corresponding to the middle or initial end of a conductive channel to be formed on the substrate surface layer in the interval, wherein a potential well varying in the depth according to the ion density acting on the sensing section is formed in the middle of the conductive channel, and the electric charge according to the seepage amount from the potential well is measured in the floating diffusion section,
a sample fixing gold electrode is fixed by way of an insulation film on the substrate surface near the sensing section, and a terminal radical of single-strand nucleic acid complementary to a DNA specimen is fixed in the gold electrode, a same sample solution is supported in a region including the sensing section and the gold electrode, and an intercalating agent for invading into DNA double helices to be formed by hybridizing to the nucleic acid fixed on the gold electrode is added, a specified voltage is applied to the gold electrode to vary the PH of the sample solution on the basis of the oxidizing and reducing current flowing between the intercalating agent between the DNA double helices and the gold electrode, and seepage charge amount from the potential well as the depth corresponding to the PH change is measured on the basis of the potential of the comparing electrode, thereby detecting presence or absence of hybridization between the single-strand nucleic acid and specimen.
Specification