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 (H2O2) 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.