Patent ID: 7105857

Claim:
A nitride semiconductor device comprising: a substrate having two opposed main faces and having a thermal expansion coefficient higher than that of a nitride semiconductor; a bonding layer placed on one main face of said substrate and comprising an eutectic layer; a p-electrode on said bonding layer; one or more p-type nitride semiconductor layers electrically connected to the p-electrode; an active layer comprising at least a well layer of Al a In b Ga 1-a-b N, (0≦a≦1, 0≦b≦1, a+b≦1) and a barrier layer of Al c In d Ga 1-c-d N, (0≦c≦1, 0≦d≦1, c+d≦1), the active layer being on said p-type nitride semiconductor layers; and one or more n-type nitride semiconductor layers on said active layer; a n-electrode electrically connected to one or more of said n-type nitride semiconductor layers; wherein said p-type nitride semiconductor layers, said active layer and said n-type nitride semiconductor layers are sandwiched between said p-electrode and said n-electrode, and wherein said n-type nitride semiconductor layers contain Al at least in a part of said n-type nitride semiconductor layers that is in contact with said n-electrode.