Ion-selective membrane chemically bound to a field-effect transistor

Abstract

A new ion-selective polymeric membrane chemically bound to a CHEMFET was realized. Instead of a traditional PVC membrane, a polymer, obtained in situ by photochemical and thermal curing, was used. The chemical adhesion of the membrane to the gate area of the FET was obtained by chemical functionalization of the SiO 2/Si 3N 4 with a polyorganosiloxane capable of reacting with the organic membrane. In this way, the ISFET stability and the reliability in aqueous solution were improved. The ISFET response was linear in the 10 −1 – 10 −4 M KCl range using valinomycin as the ionophore entrapped into the membrane.