Patent ID: 8604591

Claim:
A nitride-based semiconductor device, comprising: a nitride-based semiconductor multilayer structure including a p-type semiconductor region, a growing plane of the p-type semiconductor region being an m-plane; and an electrode that is provided on the p-type semiconductor region, wherein the p-type semiconductor region includes a contact layer which is made of an Al x Ga y In z N (x+y+z=1, x≧0, y≧0, z≧0) semiconductor, the contact layer having a thickness of not less than 26 nm and not more than 60 nm, the contact layer includes a body layer which contains Mg of not less than 4×10 19 cm −3 and not more than 2×10 20 cm −3 and a high-concentration layer which is in contact with the electrode and which has a Mg concentration of not less than 1×10 21 cm −3 , the high-concentration layer has a thickness of not less than 0.5 nm and not more than 5 nm, and a magnesium layer is deposited on a surface of the high-concentration layer.