An H⁺-ion sensor based on a gated lateral bipolar junction transistor (BJT) pair that can operate without the classical reference electrode is proposed. The device is a special type of ion-sensitive field-effect transistor (ISFET). Classical ISFETs have the advantage of miniaturization, but  they are difficult to fabricate by a single fabrication process because of the bulky and brittle referen...

Impedance spectroscopy is an electrochemical technique widely used for the electrical characterization of behavior biomaterials in all kinds biosensors. Field-effect devices, and particular ion-sensitive field-effect transistors (ISFETs), have been extensively studied as transducers biosensing. They however not much analyzed with impedance spectroscopy, because they typically generate non-Farad...

A new method is presented for the detection of an immunological reaction taking place in a membrane, which covers the gate area of an ISFET. By stepwise changing the electrolyte concentration of the sample solution, a transient diffusion of ions through the membrane-protein layer occurs, resulting in a transient membrane potential, which is measured by the ISFET. The diffusion rate is determine...

This study presents a performance analysis of low power CMOS Integrated “Current Conveyor Ion Sensitive Field Effect transistor” (CC-ISFET). The study’s main focus is on simulation of power and performance analysis of ISFET device, which is used for water quality monitoring. This approach can improve calibration of device to a fairly wide range without the use of a high speed digital processor....

Studying the acid-base properties of protein molecules led us to reconsider the operational mechanism of ISFETs. Based on the site-dissociation model, applied to the amphoteric metal oxide gate materials used in ISFETs, the sensitivity of ISFETs is described in terms of the intrinsic buffer capacity of the oxide surface,/3s, and the electrical surface capacitance, Cs. The ISFET sensitivity towa...

Application of photocurable polymers for encapsulation of ion selective field effect transistors (ISFET) and for membrane formation in chemical sensitive field effect transistors (ChemFET) during the last 20 years is discussed. From a technological point of view these materials are quite interesting because they allow the use of standard photo-lithographic processes, which reduces significantly...