Effect of nitrogen doping temperature on the resistance stability of ITO thin films

Indium tin oxide (ITO) thin films were fabricated by magnetron sputtering in the mixture of argon and oxygen. Nitrogen doping was achieved by a two-step annealing process. It was found that with increasing temperature of the first-step treatment in N₂ atmosphere up to 800 °C, more nitrogen was doped into ITO thin films. After subsequent second-step annealing in air at 1200 °C, the ITO thin films had the most stable grain size and the highest content Sn⁴⁺ donors. This makes ITO thin film subjected to annealing in N₂ at 800 °C have the excellent resistance stability for high temperature (1200 °C) strain measurement.