Effects of etch stop layer deposition conditions on stress stabilities in amorphous In-Ga-Zn-O thin film transistors

Effects of etch stop layer (ESL) deposition conditions on stress stabilities in amorphous In-Ga-Zn-O (a-IGZO) thin film transistors (TFTs) were investigated. The performances of the a-IGZO TFTs were varied depending on the flow rate of SiH₄/N₂O in chemical vapor deposition (CVD) of ESL. The threshold voltage shift after positive bias thermal stress test was decreased with increasing the flow rate of SiH₄/N₂O. The power-law time dependence on the value of the threshold voltage shift suggested the reduction of the density of the interfacial states between the ESL and the a-IGZO layers. The features were will correlated with the sheet resistances of the films, which is consistent with the above argument.