Semiconductor device

A semiconductor device comprising:

• a semiconductor substrate;
• a semiconductor laminated layer structure disposed on the substrate and comprising at least two semiconductor layers;
• a first semiconductor layer containing a first dopant impurity providing a first conductivity type, and a second semiconductor layer disposed on the first semiconductor layer, the second semiconductor layer containing the first dopant impurity in a concentration higher than in the first semiconductor layer, successively disposed on the semiconductor laminated layer structure;
• a semiconductor diode comprising a first electrode in ohmic contact with the second semiconductor layer, and a second electrode in Schottky contact with the second semiconductor layer;
• and
• a transistor including a recess in the second semiconductor layer and having a depth reaching the first semiconductor layer, a gate electrode in the recess and in Schottky contact with the first semiconductor layer, and a source electrode and a drain electrode disposed on opposite sides of the recess on the second semiconductor layer in ohmic contact with the second semiconductor layer.