Patent ID: 8802530

Claim:
A semiconductor power device, comprising: a semiconductor substrate having dopants of a first conductivity type; an epitaxial semiconductor region formed on the substrate doped with dopants of the first conductivity type to a lower doping concentration than the substrate; a trench formed in the epitaxial semiconductor region; a body region formed in the epitaxial semiconductor region proximate the trench, wherein the body region is doped dopants of a second conductivity type that is opposite the first conductivity type; a source region of the first conductivity type formed proximate the trench such that the body region is between the source region and the epitaxial region, wherein a doping concentration of the source region is greater than a doping concentration of the epitaxial semiconductor region; a thick bottom insulator formed in a lower portion of the trench; an electrically conductive gate electrode formed in the trench above the thick bottom insulator, wherein the gate electrode is electrically insulated from a bottom of the trench by the thick bottom insulator and electrically insulated from sidewalls of the trench by a gate insulator; and a region of induced net charge of the first conductivity type in the thick bottom insulator proximate an interface between the thick bottom insulator and the epitaxial semiconductor region, wherein the doping concentration of the epitaxial semiconductor region is two to three times the doping concentration for an epitaxial semiconductor region in a conventional (unshielded) MOSFET device.