FABRICATION OF A NOVEL OXYGEN SENSOR WITH CMOS COMPATIBLE PROCESSES

A novel miniature dissolved oxygen sensor as a transducer for medical and environmental measurements is fabricated with a CMOS compatible pr ocess. The sensor is designed as a three electrode system. It has a Pt recessed ultramicroelectrode array structure as working electrode, a Pt counter electrode and a Ag/AgCl reference electrode. The recessed u ltramicroelectrode array is made with a lift-off method which follows a SiO2 reactive ion etching process. Different recessed ultramicroelec trode arrays varying in diameter and spacing have been designed to stu dy the diffusion characteristic in order to find the optimal values. T he chip size is 1.5 x 4 mm(2), small enough to enable implantation. (C ) 1998 Elsevier Science S.A. All rights reserved.