Patent ID: 8648378

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, z>0); the electrode comprises a Mg layer, a metal alloy layer, and a metal layer; the Mg layer is in contact with the p-type semiconductor region; the Mg layer consists of magnesium, gallium, and nitrogen; the Mg layer is covered with the metal alloy layer; the Mg layer is made up of islands of Mg portions that are present on a surface of the p-type semiconductor region; the metal layer is made of at least one metal that would make an alloy with Mg less easily than Au; the metal alloy layer consists of magnesium and the same metal as the metal of the metal layer; and a concentration of gallium included in the Mg layer is ten times or more greater than a concentration of nitrogen included in the Mg layer.