Patent ID: 8865591

Claim:
A method for forming a n-type contact electrode on a n-type semiconductor layer of a group III nitride single crystal, wherein said method comprises; carrying out a heat treatment at a temperature of 800° C. or higher and 1200° C. or less after forming a first electrode metal layer comprising a metal layer of at least one selected from a group consisting of Ti, V, and Ta on said n-type semiconductor layer, and carrying out a heat treatment at a temperature of 700° C. or higher and 1000° C. or less after forming a second electrode metal layer including a highly conductive metal layer of metals having a work function of 4.0 eV to 4.8 eV, and a specific resistance of 1.5×10 −6 Ω·cm to 4.0×10 −6 Ω·cm on said first electrode metal layer.