Effect of contact material on amorphous InGaZnO thin-film transistor characteristics

Abstract

Amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) having several metals, namely Ag, Ti, and Mo, as the source and drain electrodes were characterized. TFTs with Ti and Mo electrodes showed drain current–gate voltage characteristics without fluctuation. However, TFTs with Ag electrodes indicated a low noisy on-state current at a large channel length under a low drain–source voltage condition. The source and drain resistances [ R s/d (Ω)] of the TFTs with each of the three metals were calculated from the I DS – V GS characteristics. The R s/d values of the Ag, Ti, and Mo samples reached 4 × 10 4 , 2 × 10 4 , and 1 × 10 4 Ω, respectively. This implies that a spatial potential barrier exists at the a-IGZO/Ag interface and that the resistance of the potential barrier changes with the application of gate voltage.