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. (C) 2011 Elsevier Ltd. All rights reserved.This research was supported by Basic Science Research Program through the National Research foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant No. 2010-0008412). J.K.J. acknowledges the support by the National Research Foundation of Korea (NRF) funded by the Converging Research Center Program through the Ministry of Education, Science and Technology (2010K001062)