Title :
Effect of top gate bias on NBIS in dual gate a-IGZO TFTs
Author :
Eunji Lee ; Delwar Hossain Chowdhury, Md. ; Jin Jang
Author_Institution :
Dept. of Inf. Display, Kyung Hee Univ., Seoul, South Korea
Abstract :
We report the effects of top gate bias (VTG) on negative bias illumination stress (NBIS) applied at bottom gate terminal in dual gate amorphous indium gallium zinc oxide (a-IGZO) thin film transistor (TFT), while transfer characteristics measured at bottom gate terminal before and after stress. NBIS in a-IGZO TFTs show negative transfer shift due to the formation of positive charges, likely ionization of oxygen vacancies (VO → VO+/VO2+) and/or hole traps in Gate insulator/a-IGZO interface and a-IGZO bulk. We observed -3.26V shift after NBIS, for -10V bias at VTG, which decreases to -1.3V for VTG = +10V. It clearly revels the formation of less defects in IGZO channel when the Fermi level is shifted upward by positive top gate bias.
Keywords :
Fermi level; amorphous semiconductors; indium compounds; negative bias temperature instability; thin film transistors; Fermi level; NBIS; bottom gate terminal; dual gate a-IGZO TFT; negative bias illumination stress; negative transfer shift; oxygen vacancies; thin film transistor; top gate bias; transfer characteristics; voltage -3.26 V; Insulators; Lighting; Logic gates; Semiconductor device measurement; Stress; Thin film transistors; Voltage measurement;
Conference_Titel :
Active-Matrix Flatpanel Displays and Devices (AM-FPD), 2015 22nd International Workshop on
Conference_Location :
Kyoto
DOI :
10.1109/AM-FPD.2015.7173215
