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 degrees C) and spin-coated hafnium oxide (HfO2) 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 5.6x10(-8) A/cm(2) 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-ON/I-OFF) of 1.2 x 10(6), a high field effect mobility of over 30 cm(2)/(V center dot s), and a subthreshold swing (SS) as low as 68 mV/dec, which approximates the theoretical value limit at 300 K.