Top-Gate Short Channel Amorphous Indium-Gallium-Zinc-Oxide Thin Film Transistors With Sub-1.2 nm Equivalent Oxide Thickness
Kaizhen Han, Subhranu Samanta, Chen Sun, Xiao Gong
Abstract
We report high performance top-gate amorphous Indium-Gallium-Zinc-Oxide thin film transistors (α-IGZO TFTs) featuring the ultra-scaled equivalent oxide thickness (EOT) of sub-1.2 nm, achieving a decent peak transconductance (Gm) of 62 μS/μm at a drain to source voltage (VDS) of 2 V (33.4 μS/μm at VDS of 1 V) and an excellent drain induced barrier lowering (DIBL) of 17.6 mV/V, for a device with a channel length (LCH) of 160 nm. The best long channel device has a subthreshold swing (SS) of 67.5 mV/decade. This is enabled by using an aggressively scaled 5 nm high-k HfO2 as the gate dielectric. In addition, temperature study has been performed on α-IGZO TFTs. The key performance figure-of-merits, like field effect mobility (μeff), show negligible degradation at high temperature, indicating the great potential of α-IGZO TFTs for various emerging applications.