Patent ID: 8309984

Claim:
A nitride-based semiconductor device, comprising: a nitride-based semiconductor multilayer structure including a p-type semiconductor region, a surface of the p-type semiconductor region being an m-plane; and an electrode that is arranged on the p-type semiconductor region, wherein the p-type semiconductor region is made of an Al x In y Ga z N semiconductor (where x+y+z=1, x≧0, y≧0, and z≧0), and the electrode includes a Mg alloy layer which is in contact with the surface of the p-type semiconductor region and which is made of Mg and a metal selected from a group consisting of Pt, Mo, and Pd, and a contact resistance of the electrode arranged on the m-plane and annealed at a temperature of 500° C. to 700° C. is less than 1.0×10 −02 Ωcm 2 , and is lower than a contact resistance when the electrode is arranged on a c-plane of the same p-type semiconductor region and annealed at a temperature of 500° C. to 700° C.