Schottky barrier diode

A Schottky barrier diode comprising:

• a semiconductor substrate made of gallium oxide;
• a drift layer made of gallium oxide, the drift layer having a lower surface contacting an upper surface of the semiconductor substrate and an upper surface positioned on a side opposite the lower surface, and the drift layer having a ring-shaped outer peripheral trench in the upper surface;
• an anode electrode brought into Schottky contact with the upper surface of the drift layer surrounded by the outer peripheral trench and filled inside the outer peripheral trench through an insulating film;
• and
• a cathode electrode brought into ohmic contact with a lower surface of the semiconductor substrate on a side opposite the upper surface thereof,
• wherein a ring-shaped back surface trench is formed in the lower surface of the semiconductor substrate such that a bottom thereof reaches the drift layer,
• wherein the cathode electrode is not present at a part of the lower surface of the semiconductor substrate that is outside an area surrounded by the back surface trench but is provided within the area surrounded by the back surface trench, and
• wherein a part of the drift layer that is surrounded by the outer peripheral trench overlaps the area surrounded by the back surface trench in a plan view.