High-breakdown gallium nitride-based field effect transistor device and manufacturing method thereof

The invention discloses a high-breakdown gallium nitride-based field effect transistor device and a manufacturing method thereof. The manufacturing method comprises the following steps of: growing a nucleating layer on a substrate; growing an aluminum-gallium-nitrogen high-resistance buffering layer with a low aluminum component on the nucleating layer; growing a high-mobility gallium nitride channel layer on the aluminum-gallium-nitrogen high-resistance buffering layer; growing a thin aluminum nitride isolating layer on the gallium nitride channel layer; growing an aluminum-gallium-nitrogen barrier layer on the aluminum nitride isolating layer; growing a thin nitride cap layer on the aluminum-gallium-nitrogen barrier layer; and forming a source electrode, a drain electrode and a grid electrode on the nitride cap layer. According to the method, the process complexity is lowered, the breakdown voltage of the gallium nitride-based field effect transistor device is increased effectively, and the mobility of electrons in a channel is increased simultaneously.