Distinguishing the Different Vth Shift Mechanisms in In₂O₃ TFTs Using Ultrafast On-the-Fly Reliability Measurements

This study presents a comprehensive investigation of the threshold voltage (V<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub>) shift mechanisms in atomic-layer-deposited (ALD) In<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> thin-film transistors (TFTs), utilizing ultrafast On-the-Fly (UF-OTF) measurements. Two distinct degradation mechanisms are identified: electron trapping and donor trap generation at the HfO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>/In<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> interface under positive bias stress (PBS), which conventional measure-stress-measure (MSM) techniques fail to effectively separate due to the inability to perform short-time measurements. Donor trap generation exhibits a strong dependence on measurement temperature, and stress degradation time, indicating a thermally activated process. Optimized oxygen annealing effectively passivates these defects, significantly reducing their impact on device instability. Temperature-dependent measurements reveal shallow electron trapping with an activation energy (E<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">τ,e</sub>) of 0.12 eV, whereas donor trap generation is characterized by an activation energy (E<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">τ,d</sub>) of 0.57 eV. These results emphasize the importance of oxygen annealing optimization, defect passivation, and self-heating mitigation to enhance the electrical performance, long-term stability, and overall reliability of high-performance In<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> TFTs for advanced electronic applications.