FIELD-EFFECT TRANSISTOR AND INTEGRATED CIRCUIT DEVICE INCLUDING THE SAME

A field-effect transistor includes an insulating barrier layer on a substrate, a gate electrode extending on the insulating barrier layer, a gate insulating layer covering opposite side surfaces and a top surface of the gate electrode, an oxide semiconductor layer on the gate insulating layer and including at least one metal element selected from indium (In) and zinc (Zn), and a source structure and a drain structure separated from each other, the source structure and the drain structure electrically connected to the oxide semiconductor layer. Each of the source structure and the drain structure includes an indium gallium tin oxide (IGTO) film on the oxide semiconductor layer, a conductive metal nitride film on the IGTO film, one of a source electrode and a drain electrode on the conductive metal nitride film, and a top capping layer on a top surface of one of the source electrode and the drain electrode.