Amorphous IGZO TFTs Featuring Extremely-Scaled Channel Thickness and 38 nm Channel Length: Achieving Record High Gm,max of 125 μS/μm at VDS of 1 V and ION of 350 μA/μm

We demonstrated amorphous indium-gallium-zinc-oxide thin film transistors (a-IGZO TFTs) with extremely scaled channel thickness t
_a-IGZO
of 3.6 nm, achieving low SS of 74.4 mV/decade and the highest μ
_eff
of 34 cm
²
/V·s at carrier density N
_carrier
of ~5 × 10
¹²
cm
^-2
for a-IGZO TFTs having sub-10 nm t
_a-IGZO
. We found that there is no obvious degradation of mobility as t
_a-IGZO
changes from 6 nm to 3.6 nm. By scaling down the channel length LCH to 38 nm, the devices have shown the highest extrinsic transconductance (G
_m
) of 125 μS/μm (at V
_DS
of 1 V) and the highest on-state current I
_ON
of 350 μA/μm at V
_GS
-V
_T
of 3.0 V and V
_DS
of 2.5 V for any kind of a-IGZO TFTs.