Patent ID: 8581336

Claim:
A trench MOSFET rectifier device, comprising: a semiconductor substrate of a first conductivity type; a first plurality of trenches in said semiconductor substrate and spaced apart by a plurality of mesa regions; a source region of first conductivity type at a surface of each mesa region; a body region of a second conductivity type beneath each source region; a dielectric layer lining the bottom and sidewall surfaces, respectively, of each of the first plurality of trenches, the portion of the dielectric layer on the bottom surface being thicker than the portion on the sidewall surface; a doped region of the second conductivity type under the bottom surface of each of the first plurality of trenches and spaced apart from each of the body regions; a polysilicon gate region filling each of the first plurality of trenches; a conductive material in ohmic contact with the source region, the body region, and the polysilicon gate region; a first electrode overlying and in contact with the conductive material; and a drain electrode on a second surface of the substrate opposite from a first surface, said first surface being an upper main surface of the substrate.