Performance and Stability Improvements of Back-Channel-Etched Amorphous Indium–Gallium–Zinc Thin-Film-Transistors by CF₄+O₂ Plasma Treatment

Abstract

The performance and stability improvement of back-channel-etched amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) by post CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> +O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma treatment is investigated. It is revealed that the metal residue of the wet-etching of source/drain electrodes degrades TFT performance and aggravates the positive threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> ) shift under positive gate bias stress. It is demonstrated that the CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> +O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma treatment effectively removes the metal residue and remarkably improves device performance and the V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> stability. This improvement is attributed to oxygen vacancy repairing at the back channel interface of the a-IGZO TFT by the O free radicals generated by the O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma.