Top-Gate Short Channel Amorphous Indium-Gallium-Zinc-Oxide Thin Film Transistors with Sub-1.2 nm Equivalent Oxide Thickness

We report high performance top-gate amorphous Indium-Gallium-Zinc-Oxide thin film transistors (α-IGZO TFTs) featuring the smallest equivalent oxide thickness (EOT) of sub-1.2 nm among all IGZO-channel TFTs, achieving the highest extrinsic peak transconductance (G
_m,ext
) of 62 μS/μm at a drain to source voltage (V
_DS
)=2V(33.4μS/μm at V
_DS
=1V) and excellent drain induced barrier lowering (DIBL) of 17.6 m V/V, for a device with a channel length (L
_CH
) of 160 nm. The best long channel device has a subthreshold swing (SS) of 67.5 mV/decade. This was enabled by using an ultra-scaled 5 nm high-k HfO
₂
as the gate dielectric. In addition, temperature study was also performed on α-IGZO TFTs. Field effect mobility (μ
_eff
) show negligible degradation at high temperature, indicating the great potential of α-IGZO TFTs for various emerging applications.