Low-Temperature Fabrication of Indium Oxynitride Thin-Film Transistors via Plasma-Assisted Solution Process
Xuyang Li, Bin Liu, Xianwen Liu, Guobin Sun, Haifeng Liang, Huan Liu, Qian Mi, Guangcai Yuan, Jianshe Xue, Zhinong Yu
Abstract
The relatively high thermal annealing (TA) temperature and long TA time during the postprocessing seriously impede the application of solution-processed routes in printable flexible metal oxide (MO) electronic devices. Here, we propose a novel low-temperature solution-processed route, which employs NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> or N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma instead of TA to treat preannealing MO thin films, for the fabrication of MO thin films at low temperatures. The results indicate that the NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> or N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> “plasma-assisted solution processes” (PASPs) make the preannealing indium oxide (InO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> ) thin films change into indium oxynitride (InON) thin films and effectively reduce the postprocessing temperature and time of InON thin films. The InON thin-film transistor (TFT) based on NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> PASP exhibits acceptable electrical characteristics with a saturation mobility ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {sat}}{)}$ </tex-math></inline-formula> of 1.30 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /Vs and an <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> of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> at 160 °C; however, there are apparent local plasma-damage regions on the surface of InON thin films. Compared to NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> PASP, the N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> PASP shows a better low-temperature activation effect while avoiding plasma damage. The InON TFT based on N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> PASP exhibits excellent electrical characteristics with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {sat}}$ </tex-math></inline-formula> of 5.91 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /Vs and <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> of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> at postprocessing temperatures as low as 100 °C and time as short as 33 min. These findings highlight the critical role of plasma treatment (PT) atmospheres in the low-temperature fabrication of the InON thin films via PASP and provide an effective low-temperature solution-processed route to guarantee the development of printable flexible MO electronic devices in the future.