An HV MOSFET device has a body integrating source conductive regions. Projecting gate structures are disposed above the body, laterally offset with respect to the source conductive regions. Source contact regions, of a first metal, are arranged on the body in electric contact with the source conductive regions, and source connection regions, of a second metal, are arranged above the source contact regions and have a height protruding with respect to the projecting gate structures. A package includes a metal support bonded to a second surface of the body, and a dissipating region, above the first surface of the semiconductor die. The dissipating region includes a conductive plate having a planar face bonded to the source connection regions and spaced from the projecting gate structures. A package mass of dielectric material is disposed between the support and the dissipating region and incorporates the semiconductor die. The dissipating region is a DBC-type insulation multilayer.