Patent ID: 8338862

Claim:
A semiconductor device comprising: a substrate on which a GaN channel layer, an AlGaN electron supply layer and a GaN cap layer are stacked in this order; a gate electrode formed on the GaN cap layer; and a source electrode and a drain electrode formed on the AlGaN electron supply layer so as to interpose the gate electrode, wherein a first recess is formed in the GaN cap layer and located between the gate electrode and the source electrode, a second recess is formed in the GaN cap layer and located between the gate electrode and the drain electrode, a thickness of the GaN cap layer in a bottom of the first recess is smaller than a thickness of the GaN cap layer located under the gate electrode; a thickness of the GaN cap layer in a bottom of the second recess is smaller than the thickness of the GaN cap layer located under the gate electrode, and an end portion of the second recess closer to the drain electrode is formed so as to extend up to a side surface of the drain electrode.