There is provided a semiconductor device including a base substrate; a semiconductor layer formed on the base substrate and having a mesa protrusion including a receiving groove; a source electrode and a drain electrode disposed to be spaced apart from each other on the semiconductor layer, the source electrode having a source leg and the drain electrode having a drain leg; and a gate electrode insulated from the source electrode and the drain electrode and having a recess part received into the receiving groove. The mesa protrusion has a superlattice structure including at least one trench at an interface between the mesa protrusion and the source electrode and between the mesa protrusion and the drain electrode, respectively, and the source leg and the drain leg are received in the trench.