High-Performance Polysilicon TFTs Using Stacked $\hbox {Pr}_{2}\hbox {O}_{3}$ /Oxynitride Gate Dielectric

In this letter, we have developed, for the first time, a stacked Pr₂O₃/SiO_xN_y gate dielectric into low-temperature polysilicon (poly-Si) thin-film transistors (TFTs). A high- performance TFT device that has a high effective carrier mobility, a high driving current, a small subthreshold swing, and a high I_ON/I_OFF current ratio can be achieved. This phenomenon is attributed to the smooth Pr₂O₃/poly-Si interface provided by the N₂O plasma treatment. The presence of the SiO_xN_y buffer layer also enhanced the electrical reliability of the Pr₂O₃ poly-Si TFT. All of these results suggest that a high-k Pr₂O₃ gate dielectric prepared under the buffer layer is a good candidate for high- performance TFTs.