Instability of Transfer and Low Frequency Noise Characteristics under Positive Bias in the InZnO Thin Film Transistors

In this paper, the positive bias instability is studied in IZO TFTs with the Al
₂
O
₃
gate oxide. The variations of the transfer curves and the low-frequency noise characteristics are measured and analyzed. The measurement results indicate that a high positive bias induces an increment both of interface traps and traps near the dielectric/channel interface. Furthermore, the distribution of localized states in the band-gap and the spatial distribution of border traps in the gate oxide are extracted. It is demonstrated that the positive bias instability close to the interface may be dominated by the variations of the deep states in the channel of IZO TFTs.