The influence of visible light on the gate bias instability of In-Ga-Zn-O thin film transistors

Abstract

We investigated the effect of photon irradiation with various energies on the gate bias instability of indium-gallium-zinc oxide transistors. The illumination of red and green light on the transistor caused positive threshold voltage (V(th)) shifts of 0.23 V and 0.18 V. respectively, while it did not affect the V(th) value in blue light after a positive bias stress. However, the stability of transistors was deteriorated with increasing photon energy after a negative bias stress: negative V(th) shifts for red (-0.23 V) and blue light (-3.7 V). This difference can be explained by the compensation effect of the electron carrier trapping and the creation of meta-stable donors via photon excitation.