A Novel Strategy to Achieve High-Performance Titanium-Doped InZnO Thin-Film Transistors Using Atomic Layer Deposition

Titanium-doped InZnO (TiIZO) thin-film transistors (TFTs) with different doping concentrations were successfully fabricated using plasma-enhanced atomic layer deposition (PEALD). Specifically, TiIZO TFTs with Ti cation doping concentration of 0.5% using tetra (dimethylamino) titanium (TDMATi) exhibited a high field-effect mobility of 51.22 cm2/Vs and a small subthreshold swing (SS) of 0.24 V/decade. Furthermore, compared to undoped IZO TFTs, TiIZO TFTs exhibited enhanced bias stability under positive and negative temperature bias stress. This improvement is attributed to the appropriate Ti doping concentration, which suppresses impurity oxygen defects, reduces the trap density at the insulator/channel interface, and introduces additional charge carriers.