Electrical stability enhancement of GeInGaO thin-film transistors by solution-processed Li-doped yttrium oxide passivation

Abstract

In this study, we investigated a method of enhancing the electrical stability of GeInGaO thin-film transistors (TFTs) using a Li-doped Y₂O₃ (YO) passivation layer (PVL). Li reduced metal hydroxide groups in the PVL, and diffused into the channel layer and reduced the oxygen vacancy at the top surface of the channel layer, which is the origin of the defect state and electrical instability. In addition, the negative-bias temperature stress (NBTS) for 3600 s improved for Li-doped YO (LYO) PVL. The threshold voltage shift decreased from -10.3 V for the YO PVL to -4.8 V for the LYO PVL, a 54% improvement.