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

Claim 16:
17. 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;
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 pH sensor further comprises a third, a fourth, a fifth and a sixth ISFET, the first, third and fifth ISFETs being pairwise identical except for a difference in one of:
sensing surface functionalisation and/or coverage,
dielectric layer material, and
transistor channel cross-sectional area and/or length;
the second, fourth and sixth ISFETs being pairwise identical except for a difference in one of:
sensing surface functionalisation and/or coverage,
dielectric layer material, and
transistor channel cross-sectional area and/or length.