| abstract |
A semiconductor device includes a first semiconductor layer formed of a nitride semiconductor above a substrate, a second semiconductor layer formed of a material including InAlN or InAlGaN above the first semiconductor layer, a third semiconductor layer formed of a material including AlN above the second semiconductor layer, a fourth semiconductor layer formed of a material including GaN above the third semiconductor layer, a gate electrode formed above the fourth semiconductor layer, and a source electrode and a drain electrode formed on any one of the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer. |