Improved Negative Bias Stress Stability of Sol-Gel-Processed Mg-Doped In2O3 Thin Film Transistors

Abstract

We demonstrate sol-gel-processed Mg-doped 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) with high performance and improved stability. To improve the performance of indium oxide, which is unstable at a high negative threshold voltage, magnesium is used to suppress oxygen vacancy formation. As the Mg doping concentration increases, the oxygen deficiencies and OH impurities decrease, resulting in a positive shift in the threshold voltage and improved stability in negative bias stress environments. In this experiment, Mg-doped (0 to 2 wt%) indium oxide TFTs are fabricated. Indium oxide prepared from a synthesized solution of an indium nitrate hydrate precursor and 2-methoxyethanol has a mobility of 17.2 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V s. 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 doped with 1 wt% Mg also show a high mobility of 11.02 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V s and a noticeable -1.5 V threshold voltage shift under negative bias stress. Our results suggest that the sol-gel-processed Mg-doped 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 are a promising candidate for use in high-stability and high-performance applications in transparent devices.