Hemt device having an improved gate structure and manufacturing process thereof

The HEMT device (20) has a body (22) including a heterostructure (25) configured to generate a 2-dimensional charge-carrier gas (30, 49); and a gate structure (33) which extends on a top surface (22A) of the body and is biasable to electrically control the 2-dimensional charge-carrier gas. The gate structure has a channel modulating region (40) of semiconductor material; a functional region (41) of semiconductor material; and a gate contact region (42) of conductive material. The functional region and the gate contact region extend on a top surface (40A) of the channel modulating region and the gate contact region is arranged laterally with respect to the functional region. The channel modulating region (40) has a different conductivity type with respect to the functional region (41).