Patent ID: 8536616

Claim:
A multilayer structure having a gallium nitride layer, comprising: a substrate; a mesh layer disposed on the substrate and having a plurality of openings for exposing the substrate; a buffer layer disposed on the substrate in the openings and essentially consisting of a plurality of nitride layers; a lower aluminum gallium nitride layer, an intermediate aluminum gallium nitride layer and an upper aluminum gallium nitride layer with different aluminum concentrations in sequence formed on the buffer layer, wherein an aluminum concentration of the lower aluminum gallium nitride layer is higher than an aluminum concentration of the intermediate aluminum gallium nitride layer, the aluminum concentration of the intermediate aluminum gallium nitride layer is higher than an aluminum concentration of the upper aluminum gallium nitride layer, and the aluminum concentration of the intermediate aluminum gallium nitride layer is decreased in an upward direction from the lower aluminum gallium nitride layer; and a gallium nitride layer disposed on the upper aluminum gallium nitride layer.