O-vacancy as the origin of negative bias illumination stress instability in amorphous In-Ga-Zn-O thin film transistors

摘要

We find that O-vacancy (Vo) acts as a hole trap and play a role in negativebias illumination stress instability in amorphous In-Ga-Zn-O thin filmtransistors. Photo-excited holes drifted toward the channel/dielectricinterface due to small potential barriers and can be captured by Vo in thedielectrics. While Vo(+2) defects are very stable at room temperature, theiroriginal deep states are recovered via electron capture upon annealing. We alsofind that Vo(+2) can diffuse in amorphous phase, including hole accumulationnear the interface under negative gate bias.