Patent ID: 8227810

Claim:
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, and 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.