Performance Enhancement of Thin-Film Transistor Based on In₂O₃:F/In₂O₃ Homojunction

Abstract

In this article, we demonstrate a high-performance thin film transistor (TFT) based on a double-stack fluorine-doped In2O3/In2O3(InFO/InO) homojunction channel. The InFO and In2O3 semiconductor thin films were fabricated by solution process and acted as front and back channels, respectively. By using the unique bandgap characteristic of fluorine dopant, the TFT based on the InFO/InO homojunction channel exhibits improved electrical performance, including a 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">$\mu _{\text {FE}}{)}$ </tex-math></inline-formula> of 5.69 cm2/Vs and a high ON/OFF current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {on}}/{I}_{\text {off}}{)}$ </tex-math></inline-formula> ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{8}}$ </tex-math></inline-formula> . X-ray photoelectron spectroscopy (XPS) analysis proves the importance of the InFO film as the front channel. Furthermore, the InFO/InO TFT was integrated with the Al2O3 dielectric. The TFT exhibits great improvement in electrical performance, including a large <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {FE}}$ </tex-math></inline-formula> of 31.49 cm2/Vs, high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {on}}/{I}_{\text {off}}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 10^{{8}}{)}$ </tex-math></inline-formula> , and a small threshold voltage of 1.4 V. These results indicate that the TFT based on InFO/InO homojunction channel exhibits great potential in the field of low-power, flexible and printable electronic devices.