Fabrication and characterization of ITO thin film resistance temperature detector

Indium-tin-oxide (ITO) thin film resistance temperature detectors (RTD) were fabricated on alumina substrates by RF sputtering in this study. The scanning electron microscope (SEM) and atomic force microscope (AFM) images show that the thin films deposited under argon and oxygen were more smooth and dense than those deposited without oxygen. The film became more stoichiometric when no more than 20sccm oxygen was introduced. The XRD result shows that ITO deposited under argon and oxygen had an In2O3 crystal structure with a preferred orientation of (222) and the film deposited without oxygen showed a preferred orientation of (400). High temperature tests revealed that the resistance changed linearly with the temperature and the RTD had different temperature coefficient of resistance (TCR) in different temperature ranges. The absolute value of TCR was large and the RTDs showed promising application at high temperature, especially from 600 °C to 900 °C.