abstract |
A nitride semiconductor device includes: a substrate; a first nitride semiconductor layer ( 1 ) located over the substrate; a second nitride semiconductor layer ( 2 ) located over the first nitride semiconductor layer ( 1 ), having a larger band gap than the first nitride semiconductor layer ( 1 ), and having a recess ( 11 ) penetrating into the first nitride semiconductor layer ( 1 ); and a third nitride semiconductor layer ( 12 ) continuously covering the second nitride semiconductor layer ( 2 ) and the recess ( 11 ), and having a larger band gap than the first nitride semiconductor layer ( 1 ); a gate electrode ( 5 ) located above a portion of the third nitride semiconductor layer ( 12 ) over the recess ( 11 ); and a first ohmic electrode ( 4 a ) and a second ohmic electrode ( 4 b ) located on opposite sides of the gate electrode ( 5 ). |