Solution-processed high-k dielectrics for low-voltage IGZO TFTs

There have been many efforts in reducing the operating voltage of thin-film transistors (TFTs) by using dielectric materials with high capacitances, such as high-k inorganic dielectrics, organic/inorganic hybrid dielectrics, and self-assembled nanodielectrics [1]. Aluminum oxide (Al₂O₃) and zirconium oxide (ZrO₂) are the representative high-k dielectric materials due to its good leakage properties from its high bandgap, high permittivity, and solution process compatibility. Using solution-based materials, simple fabrication processes, such as spin-coating, inkjet-printing, and roll-to-roll process have been extensively attempted to make electronic devices and circuits with low-cost fabrication possibilities and large-area fabrication compatibilities [2]. In this study, we report the fabrication of solution-processed indium-gallium-zinc-oxide (IGZO) TFTs which operated in low voltage regime below 5 V and their electrical characteristics.