Patent ID: 7632670

Claim:
A sensor for the detection of an analyte, the sensor comprising a substrate forming a first plate of a first capacitor, a source contact region on the substrate, a drain contact region on the substrate, a gate oxide of a transistor on the substrate between the source contact region and the drain contact region and forming an insulator of the first capacitor, a gate electrode having inner and outer faces, the inner face being smaller than the outer face and forming a second plate of the first capacitor, the outer face forming a first plate of a second capacitor connected in series with the first capacitor, the gate-electrode inner face contacting the gate oxide over a predetermined inner contact area; an electrically insulating detection electrode forming an insulator of the second capacitor and having inner and outer faces, the detection-electrode inner face contacting the gate-electrode outer face; an immobilized receptor fixed on the detection-electrode outer face for detecting a presence of the analyte and forming a second plate of the second capacitor; and an insulator body potting all of the source contact region, drain contact region, gate electrode, and gate oxide and the detection electrode except at the detection-electrode outer face carrying the immobilized receptor to form a series circuit of the two capacitors and increase a charge density toward the transistor to enhance a detection sensitivity of the transistor.