The Influence of Hydrogen on Defects of In–Ga–Zn–O Semiconductor Thin-Film Transistors With Atomic-Layer Deposition of Al₂O₃

Abstract

Hydrogen plays a crucial role in several oxide semiconductors, where the amount of hydrogen significantly influences the device performance. Thus, its manipulation in oxide semiconductors is important for device performance. In our investigation, we studied the effect of hydrogen on defects in In–Ga–Zn–O semiconductor thin-film transistors (TFTs), as it varies with Al <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> atomic layer deposition temperature. We found that the total trap-density ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N_{{\text {tot}}}$ </tex-math></inline-formula> ) extracted by the sub-threshold slope and the trap density ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N_{t}$ </tex-math></inline-formula> ) measured by low-frequency noise (LFN) as well as the density-of-states analyzed by capacitance–voltage decreased with increasing amounts of hydrogen in the oxide semiconductor. Given that LFN data show that mobility fluctuation is the major origins of noise and the front channel of TFT is a major carrier transport region, our results indicate that hydrogen effectively passivates the defects in front channel of oxide semiconductor and contributes to achieving superior device performance.