Composite terminal surface diamond high-voltage field effect transistor and manufacturing method thereof

The invention relates to a composite terminal surface diamond high-voltage field effect transistor and a manufacturing method thereof. The transistor comprises: a diamond substrate; a composite terminal surface which is located on the surface of the diamond substrate; a source electrode located at one end of the surface of the composite terminal; a drain electrode located at the other end of the surface of the composite terminal; a gate medium which is located on the surface of the composite terminal between the source electrode and the drain electrode and covers part of the source electrode and part of the drain electrode; and a gate electrode which is located on the gate medium and located between the source electrode and the drain electrode, wherein the composite terminal surface is formed by a hydrogen terminal surface and a modified terminal surface which are spaced, and the modified terminal surface is located below the drain electrode, below the gate medium between the drain electrode and the gate elec