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

Abstract

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 of74.4 mV/decade and the highest $\mu_{eff}$ of34 cm 2 /V·s at carrier density $N_{carrier}$ of ~5 × 10 12 cm-2 for a-IGZO TFTs having sub-10 nm $t_{\alpha-IGZO}$ . We found that there is no obvious degradation of mobility as $t_{\alpha-IGZO}$ changes from 6 nm to 3.6 nm. By scaling down the channel length $L_{CH}$ to 38 nm, the devices have shown the highest extrinsic transconductance $G_{m}$ of 125 $\mu\mathrm{S}/\mu\mathrm{m}$ l (at $V_{DS}$ of 1 V) and the highest on-state current ION of 350 $\mu \mathrm{A}/\mu \mathrm{m}$ at VGS-VT of3.0 Vand $V_{DS}$ of 2.5 V for any kind of a-IGZO TFTs.