A NOVEL SILICON-BASED SENSOR ARRAY WITH CAPACITIVE EIS STRUCTURES

A modified C/V (capacitance/voltage) measuring set-up for the synchron ous operation of several EIS (electrolyte- insulator-semiconductor) se nsors was developed. Therewith, the simultaneous detection of differen t substances in aqueous analytes is possible by using capacitive senso rs that can easily be manufactured. This novel method is exemplarily d emonstrated for a sensor array based on a pH-sensitive EIS structure ( Al/Si/SiO2/Si3N4) and a penicillin-sensitive EIS structure (Al/Si/SiO2 /Si3N4/penicillinase). Both sensors are connected in parallel with eac h other. By using two additional d.c, voltage sources the single C/V c urves are shifted against each other along the voltage axis. The resul ting 'step-like' C/V curve allows the distinct assignment of each step fraction to the corresponding sensor, and thus the simultaneous detec tion of the pH and penicillin concentration in a single measurement. ( C) 1998 Elsevier Science S.A. All rights reserved.