Defect Reconfiguration through Surface Functionalization by Galvanic Peeling Treatment for Reliable and Robust InGaZnO TFTs

초록

We propose a galvanic peeling treatment (GPT) process for amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs), enabling selective defect reconfiguration without inducing crystallization or phase separation, through the dissociation of metal-oxygen bonding and densification of the oxide thin-film network. The electron-driven cleavage of weak metal-oxygen bonds (i.e., Zn-OH) not only eliminates unstable Zn sites but also promotes the reinforcement of In-O coordination, thereby improving the structural robustness of the film. The GPT-treated TFTs exhibit significantly enhanced electrical characteristics, with the optimized 10 min process showing an increase in field-effect mobility from 8.4 to 13.1 cm2/V<middle dot>s, a reduced subthreshold swing from 0.28 to 0.24 V/dec More importantly, the improved film density (from 6.5 to 7.2 g/cm3) and reduced optical bandgap fluctuation were directly correlated with suppressed device-to-device variation, demonstrating excellent reproducibility and markedly improved reliability. Under current-illumination stress (CiS) and negative bias temperature illumination stress (NBTiS), the threshold voltage shift was markedly reduced from 829 to 32 mV and from -5.06 to -2.84 V, respectively, while GPT-treated TFTs maintained minimal threshold voltage shift (Delta V TH) and stable subthreshold slopes in sharp contrast to the pronounced degradation observed in pristine a-IGZO devices after 11 hours.