Oxidation of Titanium Thin Films

Abstract

Titanium thin films were exposed to an oxidizing argon atmosphere in the temperature range from 30° to 400°C. In specimens exposed to the temperature above 300°C two stages were observed. Initially, resistance increased linearly with time and temperature coefficient values were positive. After prolonged exposure resistance increased exponentially with time, and negative temperature coefficients were observed. It is suggested that this behavior results from a progressive oxidation at grain boundaries. When oxidation is complete through grain boundaries to the substrate, conduction is then dependent on a tunneling process through the semiconducting titanium oxide leading to the observed exponential temperature and time of exposure dependence.