GaN HEMT device

The utility model relates to the technical field of semiconductor devices, and discloses a GaN HEMT (High Electron Mobility Transistor) device, which is characterized in that an HEMT epitaxial layer is arranged on a substrate and comprises a nitride heterojunction; the source electrode, the drain electrode and the grid electrode are arranged on the HEMT epitaxial layer, and the grid electrode is located between the source electrode and the drain electrode; the composite passivation layer comprises a first passivation layer and a second passivation layer, the first passivation layer is arranged on the surface of the HEMT epitaxial layer between the grid electrode and the source electrode and between the grid electrode and the drain electrode, and the second passivation layer covers the source electrode, the drain electrode, the grid electrode and the first passivation layer; the first passivation layer is a Q-carbon layer or a diamond layer. Through the arrangement of the composite passivation layer, heat gene