The Effect of the Photo-Induced Carriers on the Reliability of Oxide TFTs Under Various Intensities of Light

We investigated the reliability of oxide TFTs under negative gate bias stress combined with various intensities of light having a wavelength of 400 nm. Light illumination caused a considerable V_th shift toward negative direction, as reported in previous works. However, the trapping probability of a single hole is not altered, which means that the basic mechanism of the charge trapping is not changed by light illumination. In oxide TFTs, the hole concentration at the channel and the characteristics of the gate insulator materials are the determinant factors of the reliability under light illumination.