3-T ISFET front-end utilising parasitic device capacitance

Abstract

A 3-T ion sensitive field effect transistor (ISFET) chemical sensor that utilises the parasitic drain-gate capacitance of the device is proposed. It is compact and consumes extremely low power, and at the same time is immune to capacitive division. Additionally, it provides in-pixel amplification dependent on the ratio of passivation and feedback (parasitic) capacitance. The fabricated sensor achieves 200 mV/pH sensitivity using this amplification mechanism.