Extraction Method of Trap Densities in TFTs Combining $C$ – $V$ and F-E Methods

We propose a novel extraction method of trap densities D_t in thin-film transistors, which utilizes advantages of both capacitance-voltage (C-V) and field-effect conductance (F-E) methods. First, the threshold voltage V_th is obtained from the I-V characteristics. Next, the C-V method is used below V_th. Finally, the F-E method is used above V_th, where the surface potential φ_s at V_th obtained from the C-V method is employed as an initial φ_s for the F-E method. The novel extraction method can determine D_t from the midgap to near the electrical conductive bands.