High Performance and Hysteresis-Free a-IGZO Thin Film Transistors Based on Spin-Coated Hafnium Oxide Gate Dielectrics

We report on high performance and hysteresis-free amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) employing a low temperature (200 °C) and spin-coated hafnium oxide (HfO $_{{2}}{)}$ gate dielectric. An oxygen-doped precursor solution method (ODS) was proposed to improve the dielectric properties of these films, exhibiting low leakage current density of ${5}.{6}\times {10} ^{-{8}}$ A/cm2 at 1 MV/cm, and high breakdown field strength of 7.6 MV/cm. The optimized device has a ultra-low operating voltage of 0.5 V, a low threshold voltage of 0.13 V, a high current on/off ratio ( ${I}_{\text {ON}} / {I}_{\text {OFF}}{)}$ of ${1}.{2}\times {10} ^{{6}}$ , a high field effect mobility of over 30 cm2/(V·s), and a subthreshold swing (SS) as low as 68 mV/dec, which approximates the theoretical value limit at 300 K.