Low Subthreshold Swing and High Mobility Amorphous Indium–Gallium–Zinc-Oxide Thin-Film Transistor With Thin HfO₂ Gate Dielectric and Excellent Uniformity

Abstract

We report high performance amorphous Indium-Gallium-Zinc-Oxide (${a}$ -IGZO) thin-film transistors (TFTs) with 10 nm atomic-layer-deposited HfO2 as the gate dielectric, achieving subthreshold swing (SS) of 70.2 mV/decade, high effective mobility ($\mu _{\textit {eff}}$ ) of 55.3cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /$\text{V}\cdot \text{s}$ at an inversion carrier density ($N_{\textit {inv}}$ ) of $5\times 10^{{12}}$ cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> , and large $I_{ON}/\text{I}_{OFF}$ of >10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup> . Furthermore, very good device-to-device uniformity has been confirmed by the statistical distribution of SS and maximum transconductance (Gm, max) measured from 20 pristine TFT devices. This ${a}$ -IGZO TFT has immense potential for the ultrafast and low power electronic devices for next-generation cost-effective emissive display, image sensing, and hardware for artificial intelligence (AI).