Improvement in the Negative Bias Illumination Stress Stability for Silicon-Ion Implanted Amorphous InGaZnO Thin-Film Transistors

Using ion implantation, we doped amorphous InGaZnO (a-IGZO) with Si and investigated how this doping influenced device performance. The Si doping increased the electrical conductivity of the a-IGZO films, showing that the Si doping had produced the electron carriers. The optimum oxygen partial pressure during a-IGZO deposition moved toward higher in the Si-implanted a-IGZO thin-film transistors (TFTs) than in the undoped TFTs. In the doped TFTs, the gate bias stability against negative bias illumination stress (NBIS) improved, while the mobility remained almost the same as that without Si doping. This improvement in the NBIS stability suggests that the subgap states related to oxygen-vacancies could be reduced in the Si-implanted a-IGZO film.