Remarkable Bias‐Stress Stability of Ultrathin Atomic‐Layer‐Deposited Indium Oxide Thin‐Film Transistors Enabled by Plasma Fluorination

Abstract A low‐thermal‐budget fabrication approach is developed to realize high‐performance fluorine‐doped indium oxide (In₂O₃:F) thin‐film transistors (TFTs) with remarkable bias‐stress stability. The ultrathin transistor channel layer is prepared by a re‐developed atomic layer deposition (ALD) process of using cyclopentadienyl indium(I) (InCp) and O₂ plasma to deposit a crystalline In₂O₃ film, followed by a new fluorine doping strategy to use CF₄ plasma to afford the In₂O₃:F layer. As revealed by the density functional theory (DFT) analysis, the fluorine doping can stabilize the lattice oxygen and electrically passivate the problematic V_O defects in In₂O₃ by forming the F_OF_i spectator defects. Therefore, the fabricated In₂O₃:F TFTs show simultaneously excellent electrical performance and remarkable bias‐stress stability, with high µ_FE of 35.9 cm² V⁻¹ s⁻¹, positive V_th of 0.36 V, steep SS of 94.3 mV dec⁻¹, small hysteresis of 33 mV, and small ΔV_th of −111 and 49 mV under NBS and PBS, respectively. This work demonstrates the high promise of the fluorinated ALD In₂O₃:F TFTs for the CMOS back‐end‐of‐line (BEOL) compatible technologies toward advanced monolithic 3D integration.