Investigation on the characteristics of stress-induced hump in amorphous oxide thin film transistors

In this study, we investigate the instability of amorphous oxide thin film transistors using hafnium-indium-zinc oxide under simultaneous application of light and gate dc-bias. The hump characteristics are observed after negative gate bias and light stress. Based on the positive bias-induced recovery, it is proved that photo-generated holes are trapped in the gate insulator by the electrical field enhanced by the optical energy. Moreover, from simulated electric field distribution, it is clearly revealed that the hole-trapping is localized at the edge regions of the gate insulator along channel width/length directions by electric field crowding, resulting in the hump occurrence. (C) 2011 American Institute of Physics. [doi:10.1063/1.3606538]