Improvement in negative bias stress stability of solution-processed amorphous in-Ga-Zn-O thin-film transistors using hydrogen peroxide

We have investigated the effect of hydrogen peroxide (H₂O ₂) on negative bias stress (NBS) stability of solution-processed amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). The instability of solution-processed a-IGZO TFTs under NBS is attributed to intrinsic oxygen vacancy defects (V_o) and organic chemical-induced defects, such as pores, pin holes, and organic residues. In this respect, we added H₂O₂ into an indium-gallium-zinc oxide solution to reduce the defects without any degradation of electrical performance. The field-effect mobility and sub-threshold slope of the a-IGZO TFTs were improved from 0.37 cm² V^-1 s^-1 and 0.86 V/dec to 0.97 cm² V^-1 s^-1 and 0.58 V/dec, respectively. Furthermore, the threshold voltage shift under NBS was dramatically decreased from -3.73 to -0.18 V. These results suggest that H₂O₂ effectively reduces V_o through strong oxidation and minimizes organic chemical-induced defects by eliminating the organic chemicals at lower temperatures compared to a conventional solution process.