Remarkable Bias‐Stress Stability of Ultrathin Atomic‐Layer‐Deposited Indium Oxide Thin‐Film Transistors Enabled by Plasma Fluorination
Jinxiong Li, Shanshan Ju, Yupu Tang, Jiye Li, Xiao Li, Xu Tian, Jianzhang Zhu, Qingqin Ge, Lei Lü, Shengdong Zhang, Xinwei Wang
Abstract
Abstract A low‐thermal‐budget fabrication approach is developed to realize high‐performance fluorine‐doped indium oxide (In 2 O 3 :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 O 2 plasma to deposit a crystalline In 2 O 3 film, followed by a new fluorine doping strategy to use CF 4 plasma to afford the In 2 O 3 :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 In 2 O 3 by forming the F O F i spectator defects. Therefore, the fabricated In 2 O 3 :F TFTs show simultaneously excellent electrical performance and remarkable bias‐stress stability, with high µ FE of 35.9 cm 2 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 Δ V th of −111 and 49 mV under NBS and PBS, respectively. This work demonstrates the high promise of the fluorinated ALD In 2 O 3 :F TFTs for the CMOS back‐end‐of‐line (BEOL) compatible technologies toward advanced monolithic 3D integration.