Ultrasensitive biosensors
First Claim
1. A biosensing resistor apparatus, comprisinga substrate,a conducting or semi-conducting layer with a coating, andrecognition elements attached to the surface of the coating,wherein the conducting or semi-conducting layer is doped with implants or other doping means in two or more regions, wherein one of the regions is given a lighter doping than another and therefore has higher resistance,wherein the selective doping of multiple regions allows at least one selected from the group consisting of different targets, different target concentrations, and multiple sensing objectives to be addressed.
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Abstract
The present invention is a biosensor apparatus that includes a substrate, a source on one side of the substrate, a drain spaced from the source, a conducting channel between the source and the drain, an insulator region, and receptors on a gate region for receiving target material. The receptors are contacted for changing current flow between the source and the drain. The source and the drain are relatively wide compared to length between the source and the drain through the conducting channel.
74 Citations
50 Claims
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1. A biosensing resistor apparatus, comprising
a substrate, a conducting or semi-conducting layer with a coating, and recognition elements attached to the surface of the coating, wherein the conducting or semi-conducting layer is doped with implants or other doping means in two or more regions, wherein one of the regions is given a lighter doping than another and therefore has higher resistance, wherein the selective doping of multiple regions allows at least one selected from the group consisting of different targets, different target concentrations, and multiple sensing objectives to be addressed.
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2. The biosensing resistor of claim 1, wherein the conducting or semi-conducting layer is Si, another semiconductor, a polymer, a metal, or another conducting material.
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3. The biosensing resistor of claim 1, wherein the conducting or semi-conducting layer is crystalline, poly crystalline, disordered, or amorphous.
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4. The biosensing resistor of claim 1, wherein a voltage bias or grounding of the substrate is eliminated, avoiding high electric field effects, premature breakdown and sensitivity to unwanted environmental features including moisture or humidity.
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5. The biosensing resistor of claim 1, wherein the conducting or semi-conducting layer is epitaxial semiconductor grown on a semiconductor of opposite carrier type to provide PN junction electrical isolation.
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6. The biosensing resistor of claim 1, wherein the substrate is an insulator.
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7. The biosensing resistor of claim 1, wherein the length, width, thickness, doping concentration and type of the conducting or semi-conducting layer are chosen to provide a pre-selected resistance and detection sensitivity suitable to at least one target of interest.
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8. The biosensing resistor of claim 1, further comprising a SiO2 layer immediately above the conducting or semi-conducting layer, wherein the SiO2 layer and IC processing largely eliminate surface deleterious states between the coating and the conducting or semi-conducting layer.
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9. The biosensing resistor of claim 8, further comprising a second SiO2 layer or other insulating layer applied to the underside of the conducting or semiconducting layer.
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10. The biosensing resistor of claim 1, wherein the coating is incorporated to block moisture.
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11. The biosensing resistor of claim 10, wherein the coating is 2000 Angstroms thick or more Si3N4 or other moisture blocking layer.
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12. The biosensing resistor of claim 1, further comprising two contacts, wherein the conducting or semi-conducting layer is formed in a meanderline connecting the two contacts.
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13. The biosensing resistor of claim 12, wherein the conducting or semi-conducting layer is constructed from at least one of the group consisting of epitaxial material, a mesa feature, a diffused or implanted region, an SOS structure, a polysilicon-structure, and a hetero structure.
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14. The biosensing resistor of claim 1, wherein the coating includes at least one selected from the group consisting of an insulator, a semiconductor, a metal, a polymer, a fiber layer, a biochemical material layer, and a chemical layer.
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15. The biosensing resistor of claim 14, wherein the substrate is Si or an insulator and the substrate is electrically floating, wherein the floating substrate avoids a pinch off effect in the range of sensor operation.
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16. The biosensing resistor of claim 15, wherein the pinch off effect is avoided at high resistor voltage drops.
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17. An integrated circuit incorporating the biosensing resistor of claim 1, wherein the biosensing resistor of claim 1 is placed outside of a primary integrated circuit area that is protected against moisture influences or chemical influences by insulators and packaging materials.
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18. The integrated circuit of claim 17, wherein the biosensing resistor is integrated with a remainder of the integrated circuit.
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19. The integrated circuit of claim 17, wherein the biosensing resistor is linked to a remainder of the integrated circuit in a hybrid manner.
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20. A sensor chip comprising the biosensing resistor of claim 1, electrical interconnects and contact pads.
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21. A sensor array comprising more than one of the sensors of claim 20 and addressing circuitry, A/D conversion, signal management circuits, display means, or communications means.
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22. The sensor array of claim 21, wherein the sensor array is a single chip integration, a hybrid system, or a combination of integrated chip and hybrid electronic system.
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23. A biosensing system, comprising the sensor chip of claim 20 and instrumentation to provide output information related to detection and or quantification of a target.
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24. The system of claim 23, wherein the output information includes disease diagnosis or treatment recommendations.
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25. The biosensing resistor of claim 1, further comprising an attachment region immediately beneath the recognition elements, wherein the recognition elements are selected from a group consisting of antibodies, virus, virus components, proteins, bacteria, bacterial components, oligos, RNA, nucleic acid compounds, enzymes, receptors, drugs, toxins, and other biochemical or biochemical complexes.
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26. The biosensing resistor of claim 25, wherein the attachment region is selected from the group consisting of Au, protein, polystyrene, nitrocellulose, a polymer, and a biochemical.
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27. The biosensing resistor of claim 26, wherein the attachment region can bind to many recognition elements.
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28. The biosensing resistor of claim 26, wherein the attachment region is selected from a group consisting of a nucleic acid chain and streptavidin.
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29. The biosensing resistor of claim 28, wherein the attachment region comprises streptavidin, wherein the recognition elements are prepared with a biotin linked antibody, protein, virus, virus component, protein, bacteria, bacterial component, oligo, ezymes, receptors, drugs, toxins, or other biochemical or biochemical complexes.
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30. The biosensing resistor of claim 1, further comprising an overlaying insulator on the substrate, wherein the conducting or semi-conducting layer is a semiconductor or poly-semiconductor material, of either carrier type, fabricated on the overlaying insulator.
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31. The biosensing resistor of claim 30, wherein the overlaying insulator is a polymer or biochemical layer.
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32. The biosensing resistor of claim 30, wherein the overlaying layer incorporates a biochemical or recognition element attachment material.
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33. The biosensing resistor of claim 30, wherein the overlaying insulator is silicon nitride, SiO2, or sapphire and isolates the semiconductor or poly-semiconductor from the underlying substrate.
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34. The biosensing resistor of claim 30, wherein the poly-semiconductor material is patterned using etching methods to provide geometry of interest.
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35. The biosensing resistor of claim 30, wherein the poly-semiconductor is poly-silicon.
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36. The biosensing resistor of claim 30, wherein the substrate is silicon, aluminum oxide, or some other insulator.
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37. The biosensing resistor of claim 30, further comprising an implant of dopant with high concentration on the surface of the poly-semiconductor.
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38. The biosensing resistor of claim 37, further comprising ohmic contacts on the surface of the implant.
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39. The biosensing resistor of claim 37, wherein the implant of dopant is of the same dopant type as the poly-semiconductor.
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40. The biosensing resistor of claim 37, wherein the implant of dopant is of the opposite dopant type as the poly-semiconductor, creating a PN junction isolated top resistor layer on the poly-semiconductor above a depletion region.
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41. The biosensing resistor of claim 40, wherein the top resistor layer is coated with an oxide thermally grown in a manner to minimize surface states and trap interface states and the top resistor surface is doped and selected such that top resistor surface is in accumulation or depletion.
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42. The biosensing resistor of claim 1, wherein the substrate is silicon and the epitaxial semiconductor is Si and is deposited, isolated and defined using mesa etching or doping isolation or both and further comprising Ohmic contacts to the epitaxial semiconductor to provide electrical current contact and removal of current.
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43. The biosensing resistor of claim 42, further comprising a PN junction.
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44. The biosensing resistor of claim 43, further comprising conducting interconnects attached to the Ohmic contacts for carrying current.
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45. The biosensing resistor of claim 43, wherein the coating comprises silicon nitride.
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46. The biosensing resistor of claim 45, further comprising a back gate that can be used to modify the concentration of carriers in the resistor.
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47. The biosensing resistor of claim 46, wherein the epitaxial semiconductor is doped using ion implantation or other doping.
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48. The biosensing resistor of claim 45, further comprising at least one coating of silicon oxide, wherein the at least one silicon oxide coating provides semiconductor device surface protection.
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49. The biosensing resistor of claim 48, wherein a second silicon oxide is located as a top coating.
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50. The biosensing resistor of claim 48, wherein a coating on the resistor provides an attachment material for recognition elements.
Specification