Abstract: An enhanced GaN high electron mobility transistor (HEMT) radio-frequency device and a manufacturing method thereof are provided. The enhanced GaN HEMT radio-frequency device includes a substrate, a first AlN interposed layer, a GaN buffer layer, a GaN trench layer, a second AlN interposed layer, an AlGaN barrier layer, a p-AlGaN layer, a metal drain electrode, a metal source electrode, and a metal gate electrode. Under an extremely high vacuum degree, metal Mg is doped and diffused to the AlGaN layer to form the p-AlGaN layer, and the metal Mg further forms a p-n junction with the undoped AlGaN layer, thereby depleting a two-dimensional electron gas (2DEG) under the gate. A HfO2 layer covers the metal Mg to prevent oxidation of the metal Mg.

Abstract: A preparation method of a double-T-shaped gate based on double-layer passivation accurate etching includes: sequentially growing two passivation layers on an epitaxial structure, where the two passivation layers include a bottom passivation layer and a top passivation layer; performing a first exposure on the top passivation layer and etching the top passivation layer and the bottom passivation layer in a first exposure region from top to bottom to form a gate root region; performing a second exposure on the top passivation layer and etching the top passivation layer in a second exposure region to form a lower gate cap region; and performing a third exposure on the top passivation layer to form a top gate cap exposure region and performing metal evaporation and removing a photoresist to form a double-T-shaped gate structure in the two passivation layers.