CMOS ISFET Arrays for Integrated Electrochemical Sensing and Imaging Applications: A Tutorial

Abstract

The ion-sensitive field-effect transistor (ISFET) is a type of electrochemical sensor with a wide range of applications. They offer advantages of being compatible with standard CMOS technology, a miniaturised form-factor, robustness, scalability and low power requirements to name a few. There are now many architectures and design strategies to construct ISFET-based systems in CMOS, and the appropriate choice of these depends heavily on the specifications of the intended application. This tutorial aims to give a designer the knowledge needed to make the best decisions for the required specifications by providing a background in theory and an overview of design trade-offs and existing approaches. Example designs which maximise performance in particular applications are discussed and practical considerations for simulation, layout and implementation are presented.