N2O Plasma Treatment Suppressed Temperature-dependent Point Defects Formation with Amorphous Indium-Gallium-Zinc-Oxide Thin Film Transistors

The abnormal sub-threshold leakage current is observed at high temperature in amorphous Indium-Gallium-Zinc-Oxide Thin Film Transistors (a-IGZO TFTs). To confirm this phenomenon dependence of the defects of a-IGZO active layer, the paper proposes the devices with N2O plasma treatment at a-IGZO film. This phenomenon only appears in the as-fabricated device, but not in the device with N2O plasma treatment, which is experimentally verified. N2O plasma treatment at a-IGZO TFTs enhances the thin film bonding strength which could suppress the formation of temperature-dependent point defects. The point defects could be generated from oxygen atoms have left their original sites above 400K. The N2O plasma treatment devices have better stability performance than as-fabricated devices. The results suggested that the density of point states for a-IGZO TFTs with N2O plasma treatment is much lower than that as-fabricated. The N2O plasma repairs the point defect to suppress temperature-dependent sub-threshold leakage current.