Patent ID: 7439580

Claim:
A top drain MOSgated device comprising a semiconductor body of one conductivity type; a base layer of a conductivity type opposite to said one conductivity type atop said semiconductor body; a drift region of said one conductivity type atop said base layer; a plurality of laterally spaced MOSgated cells, each of said cells comprising a body-short trench and a gate trench spaced from said body-short trench and defining a mesa between said trenches; said body-short trench and said gate trench extending generally perpendicular to the plane of said semiconductor body, and extending through said drift region and said base layer; said body-short trench having a body-short contact at the bottom thereof connecting said base layer to said semiconductor body; said gate trench having a gate oxide lining the walls thereof which extends along at least a portion of the depth of said base layer; a conductive polysilicon gate electrode filling the bottom of said gate trench; an increased conductivity drain region formed at the top of said mesa; a conductive drain front electrode connected to said increased conductivity drain region; a conductive source electrode connected to the bottom of said semiconductor body; an implant region of said one conductivity type and greater concentration of charge than said semiconductor body at bottom of said body short trench to improve the contact between said body-short contact and said semiconductor body; and a body short implant of said opposite conductivity type and a higher conductivity than said base layer which spans along said body-short trench from a lower portion of said base layer and makes contact with said body-short contact.