Influence of oxygen/argon reaction gas ratio on optical and electrical characteristics of amorphous IGZO thin films coated by HiPIMS process

Abstract High power impulse magnetron sputtering (HiPIMS) is a novel physical vapor deposition technique, especially for a low-temperature process application. In this study, the InGaZnO (IGZO) ceramic target (In:Ga:Zn:O = 1:1:1:4 in atomic ratio) was used to deposit amorphous IGZO thin film on quartz glass around 40 °C–50 °C under unipolar mode of HiPIMS. Influence of oxygen/argon reaction gas ratio with a fixed duty cycle of 3% on the amorphous IGZO thin films was investigated. During deposition process, target voltage and current were recorded. The crystal structure and surface morphology of the obtained amorphous IGZO thin films were investigated by using scanning electron microscopy and atomic force microscopy, respectively. The crystal characteristics of IGZO thin films were investigated using the transmission electron microscopy and a grazing incidence X-ray diffractometry. Compositions and chemical bonding state were analyzed using X-ray photoelectron spectra. The optical and electrical characteristics of the amorphous IGZO thin films were investigated by using UV/Visible light-absorbing detector and Hall-effect measurement instrument, respectively. In this study, it was demonstrated that HiPIMS system provides a smooth thin film coating at a low processing temperature around 40 °C–50 °C. The results revealed that the amorphous IGZO thin films grown by HiPIMS have higher optical and electrical properties and can help to better understand on the effect of argon/oxygen reaction gas ratio for the depositing characteristic of IGZO transparent conductive thin films.