Improved Electrical Performance of In₂O₃ Thin-Film Transistor by UV/Ozone Treatment
Han-Lin Zhao, Fei Shan, Xiaolin Wang, Jae‐Yun Lee, Sung‐Jin Kim
Abstract
In this work, the effect of a UV/ozone source composed of two monochromatic wavelengths of 184 nm and 254 nm irradiated upon the indium oxide film (In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) at the different irradiation times together with annealing at high temperature is explored. The results showed that the developed In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> thin-film transistors (TFTs) exposed to UV/ozone for the 40 s and annealed at 250 °C for 2 h exhibited a significantly high performance, i.e., saturation mobility of 6.1 ± 0.2 cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}/$ </tex-math></inline-formula> Vs, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{I}_{\mathrm{ on}}/\text{I}_{\mathrm{ off}}$ </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">$1.4\times10$ </tex-math></inline-formula> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> , low threshold voltage (1.5 ± 0.9 V), and a small subthreshold swing (0.25 V/dec). The in-depth analysis of the developed devices through electrical characteristics, surface morphology, and practical aspect of inverter function confirm that UV/ozone irradiation improves the surface trap density, thereby increasing the mobility, and eventually improves the gate-bias stress stability and time-dependent environmental stability. The current work supports the fact that UV/ozone can improve the electrical properties of In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> TFTs and can be used for the fabrication of cost-effective, low-temperature, and reliable electronic devices.