Patent ID: 7935983

Claim:
A nitride semiconductor device comprising: a substrate containing Si; a channel layer provided on the substrate and made of nitride semiconductor material; a barrier layer provided on the channel layer and made of nitride semiconductor material; a first and second main electrode connected to the barrier layer; a control electrode provided between the first main electrode and the second main electrode on the barrier layer; and an interconnect, the substrate including at least one layer having a resistivity of 1 kΩ·cm or more, wherein the substrate includes: a conductive Si substrate that has a resistivity less than 1 Ω·cm, and is electrically connected to the first main electrode through the interconnect; an insulating layer provided on the conductive Si substrate; and an Si layer provided on the insulating layer, wherein the Si layer is one of an n-type Si layer having a sheet doping concentration of less than 1×10 11 cm −2 and a p-type Si layer having a sheet doping concentration of 1×10 11 to 1×10 13 cm −2 .