Patent ID: 7745878

Claim:
A semiconductor power device comprising a plurality of power transistor cells surrounded by a plurality of trenches opened in a semiconductor substrate of a first conductivity type wherein said transistor cells comprising: body regions of a second conductivity type extended between said trenches encompassing source regions of said first conductivity type disposed next to a plurality of a trenched gates disposed in said trenches; a gate-to-drain shielding region formed as a body dopant region of said second conductivity type disposed below said trenched gates extending downwardly from a bottom of said trenched gates into said semiconductor substrate of said first conductivity type; and a trenched source contact disposed substantially at a central portion of a mesa area between said trenched gates wherein said trenched source contact comprises a source contact trench opened in said mesa area at a distance away from said trenched gates and is filled with a source metal for electrically connecting the source and body regions on sidewalls of said source contact trench to a source metal layer disposed on top of an insulation layer wherein a trench bottom surface of said trenched source contact is further covered with a layer of conductive material below said source metal to function as an integrated Schottky barrier diode in said transistor cell wherein a plurality of punch through prevention regions doped with a body dopant of said second conductivity type disposed immediately below said source regions and in direct contact with trench walls of said trenched source contact, wherein the plurality of punch through prevention regions forming only in the body regions of the second conductivity type.