Preparation and property of tetragonal zirconia thin films for oxygen sensor

Tetragonal yttria stabilized zirconia (YSZ) films were deposited on a silicon dioxide substrate by rf magnetron sputtering. Films were characterized by X-ray diffraction, RHEED and AFM. The X-ray diffraction peaks depended on the substrate temperature, and the highest peak was observed for films deposited at 400/spl deg/C. The temperature dependence of resistance was measured. The resistance of the YSZ film decreased rapidly with increasing temperature. An oxygen sensor with a planar structure was fabricated on a single crystal silicon wafer using the tetragonal YSZ film. The sensor showed well defined limiting-current characteristics and a sensitivity of 7.5 /spl mu/A/% at 20 mTorr.