Contact resistance asymmetry of amorphous indium–gallium–zinc–oxide thin-film transistors by scanning Kelvin probe microscopy

Wu Chen-Fei^{1, 2}, Chen Yun-Feng^{1, 2}, Lu Hai^{1, 2, †,}, Huang Xiao-Ming³, Ren Fang-Fang^{1, 2}, Chen Dun-Jun^{1, 2}, Zhang Rong^{1, 2}, Zheng You-Dou^{1, 2}

(a) Surface topography of the a-IGZO TFT along the channel length. (b) Surface potential profiles of the a-IGZO TFT with V_DS = 5 V and V_GS increases from 1 V to 15 V (each profile curve is sequentially offset by 1 V for clarity). The shaded regions depict the topographic edges of the S/D electrodes. The lines in blue indicate the potential profiles for TFTs working in the non-saturation region (V_GS−V_th>V_DS) while the lines in orange indicate the potential profiles for TFTs working in the saturation region (V_GS−V_th ≤ V_DS).