Characteristics of the PPy Material as pH Sensitive Membrane

A monolithic pH sensor system has been studied and developed, based on standard CMOS technology. The micro system includes an on-chip integration of differential ISFET/REFET sensing devices, metal constructed pseudo reference electrode (PRE) and their relative signal processing circuits. We mainly present the development of PPy(polypyrrole) membrane by the way of electrochemical polymerization, which was grown on the gate of ISFET, as pH sensitive material. With a series of experiments, a high sensitivity of 56mV/pH was achieved within the pH range from 1 to 12. In the end, we discussed the influence of reagents and polymerization parameters on the pH sensor system.