A „Hybrid“ Thin-Film pH Sensor with Integrated Thick-Film Reference

A reference electrode fabricated by means of thick-film technique is deposited onto a silicon substrate and combined with a thin-film pH sensor to a “hybrid†chip system. To evaluate the suitability of this combination, first investigations were carried out. The characteristics of the thin-film pH sensor were studied towards the thick-film Ag/AgCl reference electrode. Measurements were performed in the capacitance/voltage (C/V) and constant capacitance (Concap) mode for different pH values keeping the concentration of chloride ions constant. No difference of the sensor behaviour could be found when comparing the results to measurements, obtained versus a conventional macroscopic Ag/AgCl reference electrode.