Magnesium Oxide Films as Temperature Sensor

Abstract

Mg oxide thin films, with thermal sensitivity superior to Pt thin films, were fabricated through annealing of Mg films deposited by r.f. magnetron sputtering. The annealing was carried out in the temperature range of 500-700 °C under atmospheric conditions. Resistivity of the resulting Mg oxide films were in the range of 1.7x10⁷ µΩ-cm/°C to 2.81×10¹² µΩ-cm/°C, depending on the extent of Mg oxidation.  The temperature coefficient of resistance (TCR) of the MgO films also depended on the extent of Mg oxidation. The average TCR of MgO resistors, measured between 0 and 200°C, were 7630x10²ppm/°C for the 500°C and 2988x10²ppm/°C for 650 °C respectively. Because of their high resistivity and linear TCR, MgO thin films are superior to pure Pt thin films for flow and temperature sensor applications.