Patent ID: 8853742

Claim:
A semiconductor device, comprising: a first nitride semiconductor layer; a second nitride semiconductor layer provided on the first nitride semiconductor layer and having a band gap wider than that of the first nitride semiconductor layer; a third nitride semiconductor layer provided above the second nitride semiconductor layer; a fourth nitride semiconductor layer provided on the third nitride semiconductor layer and having a band gap wider than that of the third nitride semiconductor layer; a fifth nitride semiconductor layer provided between the second nitride semiconductor layer and the third nitride semiconductor layer to insulate the second nitride semiconductor layer and the third nitride semiconductor layer from each other; a first electrode being in contact with the second nitride semiconductor layer, the third nitride semiconductor and the fourth nitride semiconductor layer; a second electrode provided on the fourth nitride semiconductor layer; a gate electrode provided on a gate insulating layer between the first electrode and the second electrode; and a third electrode being contact with the second nitride semiconductor layer, the third electrode being provided so that the second electrode is between the third electrode and the gate electrode.