Short time helium annealing for solution-processed amorphous indium-gallium-zinc-oxide thin-film transistors

In this paper, the short time annealing effects on the solution-processed amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) were studied as a function of different ambient conditions. By comparing the effects of various inert gases as He, Ar, and N2 on the a-IGZO TFTs, it was found that the He-annealed TFTs prepared over a short annealing time of 30 min performed comparably to the 120 min N2-annealed samples. Similarities in the temperature dependency of the electrical characteristics of the He-annealed TFTs and the N2-annealed TFTs were also observed. These similarities are attributed to the high thermal speed of the He atoms, leading to a fast annealing effect. X-ray photoelectron spectroscopy results indicate that the superior performance of the short time He-annealed TFT does not originate from the difference in chemical residue such as OH-, but from the difference in active layer density.