400-V Amorphous IGZO Thin-Film Transistors With Drift Region Doped by Hydrogen

The 400-V amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) with the drift region doped by hydrogen near the drain side are demonstrated in this work. The breakdown voltage (V-BD) increases with the length of the drift region (L(drif)t), and the maximum V-BD of 406 V is achieved at the L-drift of 5 mu m for the a-IGZO TFT. The drift region endures the high-operating voltage to enhance the VBD, determined by the emission microscope (EMMI) detection and simulation. The output current of the high-voltage (HV) device with the drift region increases with the increasing doping-hydrogen flow rate. The X-ray photoelectron spectroscopy (XPS) proves that the doped-hydrogen improves the carrier concentration in the a-IGZO film. Therefore, the hydrogen doping region takes a low proportion of the whole ON-resistance (R-ON). The proposed 400-V a-IGZO TFTs exhibit the excellent R-ON versus VBD tradeoff relationship. The HV device with a drift region doped by hydrogen exhibits a negative shift of the threshold voltage (Vth) under the high bias stress (at V-d = 100V andV(g) = 5 V) becauseof the channel hot-carrier effect.