Patent ID: 11927562
Assignee: LUXEMBBOURG INSTITUTE OF SCIENCE AND TECHNOLOGY (LIST)
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A pH sensor, comprising
a chamber for receiving an electrolyte solution;
a first and a second ion-sensitive field effect transistor (ISFETs), each of the first and second ISFETs having a source terminal, a drain terminal and a transistor channel extending between the source terminal and the drain terminal;
a dielectric layer with a sensing surface arranged in the chamber so as to be contactable by the electrolyte solution, the dielectric layer separating the sensing surface from the transistor channel;
a first measurement circuit configured to measure a first source-drain resistance across the transistor channel of the first ISFET;
a second measurement circuit configured to measure a second source-drain resistance across the transistor channel of the second ISFET; and
a controller;
the first and second measurement circuits including a common reference electrode, the reference electrode arranged contactable by the electrolyte solution in the chamber;
wherein the dielectric layer of first ISFET has a first thickness and the dielectric layer of the second ISFET has a second thickness different from the first thickness;
wherein the controller is operatively connected to the first and second measurement circuits and configured to determine pH of the electrolyte solution based on the first source-drain resistance and the second source-drain resistance under the constraint of a dielectric layer degradation parameter common to the first ISFET and the second ISFET.