Patent ID: 8183596

Claim:
A high electron mobility transistor comprising: a free-standing supporting base having a III nitride region; a first III nitride barrier layer on the III nitride region; a III nitride channel layer on the first III nitride barrier layer, the III nitride channel layer forming a first heterojunction with the first III nitride barrier layer; a gate electrode provided on the III nitride channel layer so as to exert an electric field on the first heterojunction; a source electrode provided on the III nitride channel layer and the first III nitride barrier layer; and a drain electrode provided on the III nitride channel layer and the first III nitride barrier, the III nitride channel layer having compressive internal strain such that a piezoelectric field in the III nitride channel layer is oriented in a direction from the supporting base toward the first III nitride barrier layer, and the first heterojunction extending along a plane, a normal axis of the plane being inclined at an inclination angle in a range of 40 degrees to 85 degrees or 140 degrees to 180 degrees with respect to a c-axis of the III nitride region.