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) images show that the thin film was smooth and dense. The ICP test shows that the ITO has an In2O3/SnO2 weight ratio of 9.76. ITO film was an In2O3 crystal structure with a preferred orientation of (440) for the as-deposited film and showed a preferred orientation of (222) after annealing at 85 degrees C. High temperature tests revealed that the RTD had a negative temperature coefficient of resistance (TCR) of -2313 ppm C-1 from room temperature to 400 C and a positive TCR of 3552 ppm C-1 at the temperature of 400-600 degrees C. While at the range of 600-900 degrees C the TCR turned to be -2152 ppm C-1.