Sputtering process parameters to structural and electrical properties of indium zinc oxide thin films

Indium-zinc oxide (IZO) is a prominent transparent conducting oxide (TCO) for solar energy and display applications. They demonstrate higher optical transmittance (>75%) than that of aluminum zinc oxides (AZO); better resistance to water vapor than zinc oxides (ZnO); and relatively good electrical conductivity. However, the high content of indium in IZO is costly and difficult to massively fabricate. In this study, relatively low indium IZO thin films were deposited on glass substrates using magnetron sputtering with a mixed 53wt.% In₂O₃+47wt.% ZnO target. To monitor the process, both Langmuir probe and optical emission spectrometer were employed to investigate the plasma conditions. Several parameters such as plasma potential, electron and ion densities were carefully recorded and analyzed. On the other hand, the structure and electrical resistivity of films were examined by XRD and four-point probe. Finally, correlations between the process parameters (RF power) and films' properties were assessed based upon the results from the plasma diagnostics.