Patent ID: 7084034

Claim:
Process for the manufacturing of a MOS-gated power device, comprising the steps of: a) forming a semiconductor material layer of a first conductivity type and with a first resistivity value over a heavily doped semiconductor substrate of the first conductivity type; b) forming an insulated gate layer over said semiconductor material layer; c) selectively removing said insulated gate layer to open windows over selected portions of a surface of said semiconductor material layer; d) forming body regions of a second conductivity type and with a second resistivity value in said semiconductor material layer using the remaining portions of said insulated gate layer as a mask; e) forming source regions of the first conductivity type in said body regions, said process providing for forming doped regions of the second conductivity type in said semiconductor material layer, each one of said doped regions being located under a respective body region of the final power device and extending in said semiconductor material layer, wherein said doped regions of the second conductivity type under said body regions are formed implanting into said semiconductor material layer of the first conductivity type a dopant of the second conductivity type in a dose suitable to invert the first conductivity type of said semiconductor material layer; wherein said dopant of the second conductivity type implanted to form said doped regions under said body regions is a dopant having high diffusivity in said semiconductor material layer; and wherein the step of formation of the source regions comprising a selective implant of a dopant of the first conductivity type and a subsequent thermal diffusion of the implanted dopant, wherein said high diffusivity dopant implanted to form said doped regions under said body regions is implanted before the formation of said source regions, and is thermally diffused in said semiconductor material layer substantially down to said semiconductor substrate during the thermal diffusion of the dopant forming said source regions.