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

The performance and stability improvement of back-channel-etched amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) by post CF
₄
+O
₂
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
_th
) shift under positive gate bias stress. It is demonstrated that the CF
₄
+O
₂
plasma treatment effectively removes the metal residue and remarkably improves device performance and the V
_th
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
₂
plasma.