Annealing effects in ITO based ceramic thin film thermocouples

Nitrogen doped indium oxide (InON) and indium tin oxide (ITON) thin films were fabricated with reactive sputtering in nitrogen-rich plasmas for high temperature thermocouples. Different annealing processes were applied to improve the performance of indium oxide-based thin film thermocouples. The microstructural changes in the films were revealed by X-ray photoelectron spectroscopy (XPS). Metastably retained nitrogen in as-deposited film was transformed into In2O3 and/or oxynitrides after annealing. And significant improvement of linearity and high temperature stability was achieved in N2-Air annealed ITO thin-film thermocouples.