Recent progress of oxide-TFT-based inverter technology

Oxide semiconductor-based thin-film transistor (oxide-TFT) technology have gained significant attention since the innovation of n-channel oxide-TFT using ZnO and amorphous In–Ga–Zn–O (a-IGZO) channels because of their superior device properties including excellent electrical property such as high TFT mobility over >10 cm2/Vs and the low-cost manufacturability originating from the low-temperature processability. Already, n-channel a-IGZO-TFT is widely employed as a TFT pixel switching backplane for several high-performance active-matrix flat-panel displays, and oxide-TFT technology to date is well acknowledged as the best TFT technology for future device applications in the wide range area of electronics such as sensors, Internet of things (IoT), energy-harvesting, medical/bio-interface device, etc. Therefore, the development of large-scale circuit beyond discrete TFT device level becomes increasingly important and is vital to advance the next stage of oxide-TFT technology. In particular, developing oxide-TFT-based inverter device technology is the key for developing several digital and analog circuits. In this paper, the recent progress and challenges in oxide-TFT-based inverter technology, including unipolar NMOS, PMOS, CMOS, and CMOS-like inverters using ambipolar oxide-TFT, are reviewed.