Low Temperature High-k Solution Processed Hybrid Gate Insulator for High Performance Amorphous In-Ga-Zn-O Thin-Film Transistors

Low temperature process is required to fabricate high performance amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) on plastic substrates for flexible display applications. In addition, high-k material which allows higher mobility, higher drain current and lower threshold voltage while facilitating miniaturization, is poised to replace conventional SiO2 gate insulators in TFTs. Therefore, hybrid material containing high-k BaTiO3 nanoparticles and transparent Poly-siloxane (Poly-SX) were used as gate insulator in a-IGZO TFTs. Opting for a hybrid material instead of only a BaTiO3 film enables lowering of process temperatures. This paper presents the performance of a-IGZO TFTs with solution processed hybrid gate insulators at different BaTiO3/Poly-SX ratios deposited at a lower temperature (300°C). The device shows a high mobility of 30.17 cm2/Vs, low threshold voltage of 0.4 V, and leakage current density of ~10−8 A/cm2.