Insights into the properties of IGZO films and thin-film transistors fabricated by radio frequency and high-power impulse magnetron sputtering

Abstract Amorphous indium-gallium-zinc-oxide (a-IGZO) films are promising candidate for high-performance TFT devices. In this study, a-IGZO films were fabricated using radio-frequency magnetron sputtering (RFMS) and high-power impulse magnetron sputtering (HiPIMS). The detailed IGZO film deposition mechanism under RFMS and HiPIMS has been proposed and elaborated, respectively. The overall plasma intensity observed under RFMS model was higher than that of HiPIMS, particularly regarding the ratios of excited neutral radicals, which contributed to a higher deposition rate. In contrast, the proportion of positively charged ions in HiPIMS was significantly higher than that of RFMS. The atomic composition of the RFMS-deposited IGZO film was closer to the target stoichiometry and exhibited higher electron mobility. In comparison, the atomic composition of HiPIMS-deposited IGZO film slightly deviated from target. The HiPIMS-IGZO film exhibited a more compact and smoother morphology, as well as higher film density, but showed lower electron mobility and carrier concentration. Therefore, it may be necessary to tune the target atomic ratio to obtain the optimal atomic ratios of HiPIMS-IGZO film. This work provides new insights into the development of high-quality IGZO films and TFT devices using HiPIMS techniques.