Aggressively Scaled Atomic Layer Deposited Amorphous InZnO<sub>x</sub> Thin Film Transistor Exhibiting Prominent Short Channel Characteristics (SS= 69 mV/dec.; DIBL = 27.8 mV/V) and High G<sub>m</sub>(802 μS/μm at V<sub>DS</sub> = 2V)
Yan-Kui Liang, June-Yang Zheng, Yu-Lon Lin, Weili Li, Yu-Cheng Lu, Dong‐Ru Hsieh, Li-Chi Peng, Tsung-Te Chou, Chi‐Chung Kei, Chun‐Chieh Lu, Huai-Ying Huang, Yuan‐Chieh Tseng, Tien‐Sheng Chao, Edward Yi Chang, Chun-Hsiung Lin
Abstract
In this work, we reported aggressively scaled amorphous InZnO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> ($\alpha$-IZO) thin film transistor (TFT) in channel length (L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ch</inf> =8 nm) and thickness (2 nm) as a promising candidate for monolithic three-dimensional (M3D) integrations at back-end-of-line (BEOL). The bottom gate TFT with ultra-short L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ch</inf> of 8 nm exhibited excellent sub-threshold swings (SS) value of 69 mV/dec, high filed-effect mobility ($\mu_{F}E$) of $41 cm^{2}/V-s$ and on-current density (I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</inf> ) up to $575 \mu A\ \mu m (V_{DS} = 1V, V_{G}|= 2V)$ with outstanding maximum transconductance (Gm) value of $521 \mu S \mu m (V_{D}S = 1 V) $. In particular, the maximum Gm reaches 802 $\mu S \mu m$ at $V_{DS}= 2V$ and very low drain induce barrier lowering (DIBL) performance of 27.8 mV/V represent the best Gm and DIBL values reported for ternary amorphous oxide-semiconductor based TFTs. Furthermore, the highly stable device characteristics of the TFT was demonstrated with positive gate bias stress (PBS), the threshold voltage shift $\left(\Delta \mathrm{V}_{t h}\right)$ of 26.5 mV (L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ch</inf> =50 nm) after 3000 s stress with VG-Vth of 3 V was observed