Electrochemical sensor, and a method of forming an electrochemical sensor

A method of manufacturing an electrochemical sensor, comprising:

• forming an insulating layer on a substrate;
• providing at least one hole in the substrate;
• providing an opening in the insulating layer;
• forming at least one porous electrode in the opening in the insulating layer such that the at least one electrode is exposed to the environment through the substrate;
• forming at least one additional electrode, over the insulating layer;
• forming a layer of electrolyte over the electrodes and the insulating layer;
• and
• wherein the at least one porous electrode is substantially circular, and the other of the at least one additional electrode is partially-annular and formed around the periphery of the at least one porous electrode.

An electrochemical sensor comprising:

• a substrate;
• an insulating layer;
• at least two electrodes, wherein at least one of the at least two electrodes being a porous electrode;
• an electrolyte;
• a ring-shaped conductive track, coaxial with and positioned beneath the at least one porous electrode;
• and
• wherein the at least one porous electrode is formed in an opening in the insulating layer, the electrolyte is formed as a layer over the electrodes and the insulating layer, the substrate has at least one hole formed therein, and the sensor is arranged such that the porous electrode is exposed to the environment through the at least one hole in the substrate.