Patent ID: 8129748

Claim:
A nitride semiconductor FET comprising: a first nitride semiconductor layer formed over a substrate; a second nitride semiconductor layer formed on the first nitride semiconductor layer and having a wider band gap than the first nitride semiconductor layer; a third nitride semiconductor layer which is formed on the second nitride semiconductor layer and which includes a control region with a p-type conductivity and high resistive region formed around the control region and having a higher resistance than that of the control region; a gate electrode formed on the control region; a source electrode formed on a first side of the gate electrode; and a drain electrode formed on a second side of the gate electrode which is different from the first side of the gate electrode, wherein the control region and the high resistive region contain a group III element, and an amount of the group III element in the control region is substantially the same as an amount of the group III element in the high resistive region, the gate electrode makes an ohmic contact with the control region, and the high resistive region is disposed between the gate electrode and the source electrode, and between the gate electrode and the drain electrode.