Title :
Effects of High-Temperature Annealing on Operation Characteristics of a-In-Ga-Zn-O TFTs
Author :
Hanyu, Yuichiro ; Abe, Kiyohiko ; Domen, Kay ; Nomura, Keigo ; Hiramatsu, Hidenori ; Kumomi, Hideya ; Hosono, Hideo ; Kamiya, Toshio
Author_Institution :
Mater. & Struct. Lab., Tokyo Inst. of Technol., Yokohama, Japan
Abstract :
We report operation characteristics of amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) annealed in dry O2 at temperatures up to 700 °C. The largest TFT mobilities were obtained by annealing at 200 °C-300 °C and the smallest subthreshold voltage swing ( S) was obtained at 200 °C, while those annealed at higher T exhibited poorer mobilities and S values. The TFTs annealed at ≥ 600 °C were crystallized and exhibited further poorer characteristics probably due to grain boundary issues; while, the deterioration by the 400 °C-500 °C annealing is attributed to depletion of hydrogen and consequent de-passivation effects. Device simulations and photoresponse spectroscopy extracted systematic variation of trap densities in the a-IGZO layer.
Keywords :
III-V semiconductors; annealing; gallium compounds; indium compounds; thin film transistors; zinc compounds; In-Ga-Zn-O; S values; TFT annealing; TFT mobility; a-IGZO thin-film transistors; amorphous IGZO thin-film transistors; crystallization; de-passivation effect; device simulation; grain boundary issue; high-temperature annealing effect; hydrogen depletion; operation characteristics; photoresponse spectroscopy; subthreshold voltage swing; systematic variation; temperature 200 degC to 300 degC; temperature 400 degC to 500 degC; trap densities; Annealing; Electron traps; Films; Photonics; Spectroscopy; Thin film transistors; Voltage measurement; Amorphous materials; defect; hydrogen passivation; thin-film transistors (TFTs);
Journal_Title :
Display Technology, Journal of
DOI :
10.1109/JDT.2014.2352860
