A titanium dioxide-based MOS hydrogen sensor

Abstract

This paper deals with a Pd-gate MOS hydrogen sensor using titanium dioxide as an insulator. The Pd-gate MOS capacitor was fabricated on p-type 〈111〉 silicon wafer having resistivity 3-5 Ω-cm. The titanium dioxide thickness in such a sample was about 0.5 μm. The capacitance and conductance vs voltage characteristics of the fabricated device have been studied. Such titanium dioxide based MOS capacitor showed significant change in capacitance value and also parallel shifting of conductance peak at room temperature when exposed to hydrogen. The device exhibits better sensitivity to hydrogen at zero gate bias. The fixed surface state density in such a device is found to increase linearly upon exposure to hydrogen. © 1990.