First Demonstration of BEOL-Compatible ALD-Deposited 2 nm-Thick Indium-Tungsten-Tin-Oxide (IWTO) TFTs with Superior Short-Channel Electrical Characteristics: Achieving Enhancement-Mode $\mathrm{V}_{\text{TH }}, \mathrm{I}_{\text{ON } / \text{OFF }}&g

This work successfully demonstrates ALD-derived ultra-thin amorphous indium-tungsten-tin-oxide (a-IWTO) TFTs with a channel thickness (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{T}_{\text{CH}}$</tex>) of 2 nm. Two distinct a-IWTO compositions were systematically investigated, resulting in devices with exceptional electrical performance including a high on/off current ratio (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{I}_{\text{ON}} / \mathrm{I}_{\text{OFF}}$</tex>) exceeding 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup>, a low subthreshold swing (SS) of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$63.3 \text{mV} / \text{dec}$</tex>, a small DIBL of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$37.8 \text{mV} / \mathrm{V}$</tex>, enhancement-mode operation, and negligible <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\text{TH}}$</tex> roll-off following oxygen annealing at a short channel length of 70 nm. These results demonstrate the competitive performance of IWTO TFTs compared to state-of-the-art amorphous oxide semiconductor devices.