Ion-controlled diode
AssigneeUniversity of Pennsylvania
InventorJay N. Zemel
Life of this patent
Estimating the term…
Abstract
Disclosed is an ion-controlled device for providing an electrical indication of a specific ion concentration in a fluid. An ion-sensitive membrane is placed over the junction of a gate controlled diode whose impedance is being measured. An external reference electrode is biased such that an inversion layer forms in the semiconductor material near the ion-sensitive membrane. Changes in the concentration of the unknown ion in fluid passing over the ion-sensitive membrane will affect the inversion layer in the gate controlled diode. The change in inversion layer will result in measurable changes in the diodes impedance.
Claims12
An ion sensor for sensing the presence and/or concentration of an ion in a fluid, said sensor comprising:
- an insulated semiconductor diode having a P/N junction;
- and
- an ion-sensitive membrane, separating said junction from said fluid and juxtaposed with said junction.
A chemical sensor, in combination with a means for measuring impedance of a semiconductor junction and a means for redistributing charges between a semiconductor diode and a membrane, for measuring the presence and concentration of a desired ion in a fluid, said sensor comprising:
- semiconductor diode means, having an inversion layer, for varying impedance in response to changes in said inversion layer;
- and
- membrane means, separating said diode means from said fluid, for changing the inversion layer in said diode means in response to changes in said desired ion concentration.
A chemical sensor for sensing the presence and/or concentration of a desired chemical ion in a fluid comprising:
- semiconductor diode means having an inversion layer;
- membrane means, responsive to said diode means and said fluid and adjacent to and separating said diode means from said fluid, for reducing said inversion layer in response to said ion;
- means, responsive to said diode means and said membrane means, for redistributing charges between said semiconductor diode means and said membrane means;
- and
- means, responsive to said diode means, for measuring the impedance change of said semiconductor diode means, said impedance change indicative of the presence and concentration of said ion in said fluid.
Dependencies are inferred from the claim text.