Electrical Properties of Amorphous-Indium-Gallium-Zinc-Oxide Based Thin-Film Transistors with Four Terminal Configuration

摘要

This study extracted the intrinsic device properties of indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) from four terminal (4T) measurements and compared them with the extrinsic properties which were deduced from conventional two terminal (2T) measurements to explore the effects of any resistances, including the source/drain metal contacts and the channel, on the IGZO TFT properties. For operation in the linear region at low V-DS, the intrinsic channel (RCh-intrinsic) and contact resistances (RC-intrinsic), which were higher than the extrinsic channel (RCh-extrinsic) and contact ones, respectively, were of the same order of magnitude (183 k Omega at V-GS = 10 V), indicating that the operation of the TFTs is governed by both the intrinsic channel and intrinsic contact resistances. The developed TFTs also exhibited an intrinsic 4T linear mobility of 4.4 cm(2)/Vs, which is about 61% lower than the extrinsic 2T one. This was attributed to the higher value of RCh-intrinsic compared to RCh-extrinsic.