Analysis of temperature-dependent electrical characteristics in amorphous In-Ga-Zn-O thin-film transistors using gated-four-probe measurements

We analyzed the temperature-dependent electrical characteristics of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) using a gated-four-probe method (GFP) with temperatures ranging from 93 to 373 K. The intrinsic field-effect mobility and source/drain parasitic resistance were separately extracted using the GFP method. We found that temperature-dependent transfer characteristics originated from the temperature-dependent intrinsic field-effect mobility of the a-IGZO TFTs. The parasitic resistance was also correlated with the intrinsic-field effect mobility, which decreases as the intrinsic field-effect mobility increases, indicating that access parasitic resistance originated from bulk regions rather than metal/semiconductor junction barrier is a key factor to determine the parasitic resistance of a-IGZO TFTs.