Improved Electrical Performance of Oxide Transistor Utilizing Gallium Doping Both in Channel and Dielectric Layers

Here, we report a new strategy to fabricate high performance thin-film transistors (TFTs) by doping gallium (Ga) both in channel (In ₂ O ₃ ) and dielectric (Al ₂ O ₃ ) layers. The influence of Ga doping on the microstructure and surface morphology of In ₂ O ₃ films, as well as the oxygen defects states and electrical properties of Al ₂ O ₃ films have been systematically investigated. The results show Ga doping frustrates In ₂ O ₃ crystallization and flattens film surface. As for Al ₂ O ₃ , Ga doping increase the dielectric constant, reflective index and decrease the leakage current density. Furthermore, metal oxide TFTs were developed when using In ₂ O ₃ :Ga as the channel and Al ₂ O ₃ :Ga as the dielectric layers. The devices show improved electrical performance and enhanced positive and negative bias stress stability than undoped devices.