Semiconductor device and method for manufacturing same

A semiconductor device comprising:

• a field effect transistor (FET) including a first conductivity type drift layer and constituting a switching element in a first region of a substrate having a GaN layer that is in ohmic contact with a supporting substrate;
• and
• a Schottky barrier diode (SBD) having an electrode that is in Schottky contact with a first conductivity type layer located in a second region of the substrate,
• wherein the FET and the SBD are arranged in parallel,
• a backside electrode of the FET and a backside electrode of the SBD are formed on a back of the substrate,
• comprising a second conductivity type layer and a first conductivity type cap layer formed on the first conductivity type drift layer in the first region and each having an opening formed therein, wherein a cylindrical channel-forming portion of the FET is located so as to contact an inside surface of the opening, a gate electrode is located so that the gate electrode and an inside surface of the second conductivity type layer in the opening sandwich the channel-forming portion, and the second conductivity type layer extends from the first region to the second region and directly contacts a Schottky electrode of the SBD,
• wherein the cylindrical channel-forming portion is a regrown layer that includes a first GaN-based semiconductor layer through which carriers transit and a second GaN-based semiconductor layer having a band gap larger than that of the first GaN-based semiconductor layer, and
• further comprising an interlayer insulating film that covers the gate electrode in the FET, wherein an upper electrode, of the FET, that is not covered with the interlayer insulating film and the Schottky electrode of the SBD corresponding to the FET are electrically connected to each other through a common wiring layer.