High-Performance Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors With HfOxNy/HfO2/HfOxNy Tristack Gate Dielectrics

We have fabricated and investigated amorphous indium gallium zinc oxide (alpha-IGZO) thin-film transistors (TFTs) by using HfOxNy/HfO2/HfOxNy (NON) as the gate dielectric. The NON tristack dielectric structure can increase the gate capacitance density, effectively improve interface properties of both the gate/dielectric and dielectric/active channels, suppress the charge trap density, and reduce the gate leakage. The alpha-IGZO TFT (W/L = 200/10 mu m) with NON shows superior performance such as a saturation current of 0.33 mA, an ON/OFF-current ratio of 2.2 x 10(6), a saturation mobility of 10.2 cm(2)/V . s, a source/contact resistivity of 83 Omega . cm, a subthreshold swing of 0.13 V/dec, and enhanced stressing reliability.