Method for fabricating a III-nitride semiconductor device

A method of fabricating a III-nitride semiconductor device, said method comprising:

• forming a field dielectric body and a gate dielectric body on a III-nitride multi-layer body, said III-nitride multi-layer body including an active III-nitride heterojunction;
• forming a barrier body over said gate dielectric body and a portion of said field dielectric body;
• forming a conductive gate body over said barrier body, said conductive gate body and said barrier body forming a gate electrode, wherein said barrier body prevents diffusion of said conductive gate body into said gate dielectric body;
• forming a power electrode, wherein a portion of said barrier body is disposed between said power electrode and said field dielectric body.