Integrated edge structure for high voltage semiconductor devices and related manufacturing processs

A semiconductor device comprising:

• a PN junction capable of withstanding a high reverse voltage, said PN junction including a diffused region of a first conductivity type which extends into a semiconductor material layer of a second conductivity type;
• and
• an integrated structure that spreads a depletion layer of the PN junction, said integrated structure that spreads the depletion layer of the PN junction including:
• a first lightly doped ring of the first conductivity type formed in a first lightly doped epitaxial layer of the second conductivity type, the first lightly doped ring surrounding and being merged with said diffused region of the PN junction;
• and
• a second lightly doped ring of the first conductivity type formed in a second lightly doped epitaxial layer of the second conductivity type lying over the first lightly doped epitaxial layer, the second lightly doped ring having at least one portion superimposed on and merged with the first ring, the second ring surrounding said diffused region of the PN junction.