We fabricated the electrolyte-insulator-semiconductor (EIS) devices with various high-k sensing membranes to realize a high quality pH sensor. The sensing properties of each high-k dielectric material were compared with those of conventional SiO2 (O) and SiO2/Si3N4 (ON) membranes. As a result, the high-k sensing membranes demonstrated better sensitivity and stability than the O and ON membranes. Especially, the SiO2/HfO2 (OH) stacked layer showed a high sensitivity and the SiO2/Al2O3 (OA) stacked layer exhibited an excellent chemical stability. In conclusion, the high-k sensing membranes are expected to have excellent operating characteristics in terms of sensitivity and chemical stability for the biosensor application.
