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.