High-performance CF₄ plasma treated polycrystalline silicon thin-film transistors using a high-k Tb₂ O₃ gate dielectric

In this letter, we have developed a high-k Tb₂ O₃ gate dielectric polycrystalline silicon (poly-Si) thin-film transistors (TFTs) prepared under a CF₄ plasma treatment. A high-performance TFT device that has a low threshold voltage of 0.89 V, a high effective carrier mobility of 59.6 cm² /V s, a small subthreshold swing of 212 mV/dec, and a high ION / IOFF current ratio of 8.15× 10⁶ can be achieved. This phenomenon is attributed to fluorine atoms into poly-Si films can effectively passivate the trap states near the Tb₂ O₃ /poly-Si interface. The fluorine incorporation also enhanced electrical reliability of the Tb₂ O₃ poly-Si TFT. All of these results suggest that the CF₄ plasma-treated poly-Si Tb₂ O₃ TFT is a good candidate for high-performance TFTs.