Indium-Tin-Oxide Transistor with Maximum Transconductance Over $1100 \mu \mathrm{S} / \mu \mathrm{m}$ and Cut-Off Frequency of 23 GHz

In this work, we demonstrate high performance Indium-Tin-Oxide (ITO) field-effect transistors (FETs) featuring offset top-gate (OTG) design. A record-high maximum transconductance (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$G_{\mathrm{m}, \max}$</tex>) of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1187 \mu \mathrm{S} / \mu \mathrm{m}$</tex> among all reported ITO FETs and one of the best cut-off frequency (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{\mathrm{T}}$</tex>) among amorphous oxide semiconductor (AOS) FETs reaching 23 GHz have been achieved by scaling the gate length <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\left(L_{\mathrm{G}}\right)$</tex> down to 100 nm. In addition, our investigation suggests that the substantial reduction in ITO sheet resistance (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R_{\text{sh}}$</tex>) after the atomic layer deposition (ALD) is essential to realize the high drive current observed in our devices.