Indium-Tin-Oxide Thin-Film Transistors With High Field-Effect Mobility (129.5 cm <sup>2</sup> /V⋅s) and Low Thermal Budget (150 °C)
Kaizhen Han, Yuye Kang, Xuanqi Chen, Yue Chen, Xiao Gong
Abstract
In this letter, we demonstrate high performance Indium-Tin-Oxide thin-film transistors (ITO TFTs) with low thermal budget of process temperature less than 150 °C and a record high peak field-effect mobility ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {eff}}{)}$ </tex-math></inline-formula> of 129.5 cm2/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}\cdot \text{s}$ </tex-math></inline-formula> among any kind of oxide semiconductor (OS) based TFTs with sub-5 nm channel thickness. In addition, the TFTs realized in this work also achieve decent features in terms of other key figure-of-merits, such as high on/off ratio, low drain-induced-barrier-lowering (DIBL), and a small frequency dispersion of the capacitance-voltage (C-V) characteristics. With further benefit of an raised S/D structure and by scaling the channel length ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}_{\text {CH}}{)}$ </tex-math></inline-formula> of the device down to 50 nm, it presents an extremely high on-state current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {on}}{)}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1260.9 ~\mu \text{A}/\mu \text{m}$ </tex-math></inline-formula> at a gate overdrive voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {ov}}$ </tex-math></inline-formula> of 4 V and a moderate drain to source voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {DS}}$ </tex-math></inline-formula> of 0.5 V as well as one of the best peak extrinsic transconductance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${G}_{\text {m, {ext}}}{)}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$458 ~\mu \text{S}/\mu \text{m}$ </tex-math></inline-formula> at a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {DS}}$ </tex-math></inline-formula> of 0.5 V among OS-TFTs.