Sputtered In2O3 and ITO thin films containing zirconium

Additions of Zr to In2O3 (IO) and In2O3:SnO2 (ITO) sputtered thin films are studied. We find that Zr allows IO-based films to maintain optical transparency as oxygen partial pressure in the sputter ambient decreases, and it also maintains high carrier concentration as the oxygen partial pressure increases. Applying this guidance could indicate pathways to improve film properties in large-area deposition systems. We also find that for films deposited at optimum oxygen partial pressure, the optical transparency of the IO-based films improves as Zr is added, especially in the near-infrared spectral region. Analysis of these films using Drude theory approximations indicate that optical improvement is due to an increase in dielectric permittivity caused by Zr addition. We propose that controlling dielectric permittivity may be an important strategy in improving other transparent conducting oxides (TCOs), as well as indicative of an important pathway to developing new TCOs.