The Si3N4/Si ion-sensitive semiconductor electrode

In this paper we investigate the suitability of silicon nitride as a pH-sensitive coating in the EIS (electrolyte-insulator-semiconductor) half cell. The admittance of the EIS capacitor is measured at various pH. The role of the nitride as both gate insulator and ion conducting glass is presented. Hysteresis effects ascribed to changes in the depth of ionic penetration in the Si3N4are found to be significant. We conclude that the dual use of the "gate insulator" as both insulator and ion-conducting material does not appear to be the best route for preparing ion-sensitive semiconductor electrodes.