High Performance and Hysteresis-Free a-IGZO Thin Film Transistors Based on Spin-Coated Hafnium Oxide Gate Dielectrics
Haonan Liu, Lixin Jing, Kexin He, Dandan Qu, Yushan Li, Takeo Minari, Ruiqiang Tao, Xubing Lu, Jun‐Ming Liu
Abstract
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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{2}}{)}$ </tex-math></inline-formula> 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${5}.{6}\times {10} ^{-{8}}$ </tex-math></inline-formula> 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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {ON}} / {I}_{\text {OFF}}{)}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${1}.{2}\times {10} ^{{6}}$ </tex-math></inline-formula> , 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.