Simulation of an Ion-Sensitive Field-Effect Transistor (ISFET)

Application ID: 45341

An ion-sensitive field-effect transistor (ISFET) is constructed by replacing the gate contact of a MOSFET with an electrolyte of interest. The concentration of a specific ionic species in the electrolyte can be determined by measuring the change in the gate voltage due to the interaction between the ions and the gate dielectric.

This tutorial of an ISFET pH sensor illustrates the procedure to set up the coupling between the semiconductor model and the electrolyte model. It also shows the technique of using a simple global equation to extract operating parameters, without the need to explicitly model the actual feedback circuitry.

This model example illustrates applications of this type that would nominally be built using the following products: