An integrated power MOSFET device formed by a substrate); an epitaxial layer of N type; a sinker region of P type, extending through the epitaxial layer from the top surface and in electrical contact with the substrate; a body region, of P type, extending within the sinker region from the top surface; a source region, of N type, extending within the body region from the top surface, the source region delimiting a channel region; a gate region; a source contact, electrically connected to the body region and to the source region; a drain contact, electrically connected to the epitaxial layer; and a source metallization region, extending over the rear surface and electrically connected to the substrate and to the sinker region.