Hemt device having an improved gate structure and manufacturing process thereof

The HEMT device has a body including a heterostructure configured to generate a 2-dimensional charge-carrier gas; and a gate structure which extends on a top surface of the body and is biasable to electrically control the 2-dimensional charge-carrier gas. The gate structure has a channel modulating region of semiconductor material; a functional region of semiconductor material; and a gate contact region of conductive material. The functional region and the gate contact region extend on a top surface of the channel modulating region and the gate contact region is arranged laterally with respect to the functional region. The channel modulating region has a different conductivity type with respect to the functional region.