Amorphous InGaZnO Thin-Film Transistors With Sub-10-nm Channel Thickness and Ultrascaled Channel Length
Subhranu Samanta, Kaizhen Han, Chen Sun, Chengkuan Wang, Annie Kumar, Aaron Thean, Xiao Gong
Abstract
We investigate the effect of channel layer thickness on effective mobility (μeff) in the sub-10-nm regime of amorphous indium-gallium-zinc-oxide thin-film transistors (α-IGZO TFTs). TFT devices with extremely scaled channel thickness tα-IGZO of 3.6 nm were realized, exhibiting low subthreshold swing (SS) of 74.4 mV/decade and the highest effective mobility μeff of 34 cm2/V·s at a carrier density NCarrier of ~5×1012 cm-2 for any kind of α-IGZO TFTs having sub-10-nm tα-IGZO. No significant degradation of μeff is observed as α-IGZO thickness reduced from 6 to 3.6 nm. By scaling down the channel length LCH to 38 nm, high extrinsic transconductance (Gm,max) of 125 μs/μm (at VDS of 1 V) and ON-state current ION of 350 μA/μm at VGS-VT of 3 V with VDS of 2.5 V are achieved.