Title :
Low-Voltage a-InGaZnO Thin-Film Transistors With Anodized Thin HfO2 Gate Dielectric
Author :
Yang Shao ; Xiang Xiao ; Xin He ; Wei Deng ; Shengdong Zhang
Author_Institution :
Sch. of Electron. & Comput. Eng., Peking Univ., Shenzhen, China
Abstract :
Low-voltage amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) with thin HfO2 gate dielectric grown by anodic oxidation (anodization) method are investigated. The morphological and electrical properties of the anodized thin HfO2 film are studied. It is shown that the as-grown HfO2 film with an equivalent oxide thickness of 3.8 nm has a low leakage current density of 3.6 × 10-8 A/cm2 at 1 MV/cm and high dielectric constant of ~21. The room-temperature fabricated a-IGZO TFTs with the anodized HfO2 gate dielectrics exhibit a low threshold voltage of -0.15 ± 0.08 V, small subthreshold swing value of 109 ± 4 mV/decade, reasonable saturation mobility of 8.1 ± 0.2 cm2/Vs, and an ON/OFF current ratio exceeding 1 × 107.
Keywords :
amorphous semiconductors; anodisation; crystal morphology; electric properties; hafnium compounds; indium compounds; thin film transistors; HfO2; InGaZnO; amorphous semiconductor; anodic oxidation method; anodization method; anodized thin gate dielectric; electrical properties; low voltage thin film transistor; morphological properties; Annealing; Dielectrics; Films; Hafnium compounds; Logic gates; Thin film transistors; Amorphous indium-gallium-zinc oxide (a-IGZO); anodized HfO2; high-k; low voltage; thin-film transistors (TFTs);
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2015.2422895
