Trench MOS Schottky diode

A trench MOS Schottky diode, comprising:

• a first semiconductor layer comprising a Ga2O3-based single crystal;
• a second semiconductor layer that is a layer laminated on the first semiconductor layer and that comprises a Ga2O3-based single crystal and a trench opened on a surface thereof opposite to the first semiconductor layer;
• an anode electrode formed on the surface of the second semiconductor layer opposite to the first semiconductor layer;
• a cathode electrode formed on a surface of the first semiconductor layer opposite to the second semiconductor layer;
• an insulating film covering an inner surface of the trench of the second semiconductor layer;
• and
• a trench MOS gate that is buried in the trench of the second semiconductor layer so as to be covered with the insulating film and is in contact with the anode electrode,
• wherein the second semiconductor layer comprises a lower layer on a side of the first semiconductor layer and an upper layer on a side of the anode electrode having a higher donor concentration than the lower layer.