Patent ID: 8860130

Claim:
A semiconductor power device comprising: a semiconductor substrate of a first conductivity type including a plurality of deep trenches; an epitaxial layer filling said deep trenches, the epitaxial layer further including a top epitaxial layer disposed above the deep trenches and covering a top surface of said semiconductor substrate, wherein the epitaxial layer having a second conductivity type opposite the first conductivity type; a plurality of trench MOSFET cells disposed in said top epitaxial layer with the top epitaxial layer constituting a body region and the semiconductor substrate constituting a drain region wherein the epitaxial layer in the deep trenches is charge-balanced with the semiconductor substrate surrounding the deep trenches; and each of said plurality of trench MOSFET cells further including a trench gate filled with a gate polysilicon therein and padded with a gate insulation layer wherein the trench gates having a depth shallower than the top epitaxial layer of the trench MOSFET cells.