Patent ID: 8362552

Claim:
A semiconductor device formed on a substrate having a top surface, comprising: a drain; an epitaxial layer overlaying the drain; and an active region comprising: a body disposed in the epitaxial layer; a source embedded in the body; a gate trench extending into the epitaxial layer; a gate disposed in the gate trench; a contact trench extending through the source and at least part of the body; a contact electrode disposed in the contact trench; a diode enhancement layer disposed at least in part along a contact trench wall and at least in part along bottom of the contact trench; an epitaxial enhancement portion disposed below the diode enhancement layer; wherein the epitaxial enhancement portion has the same carrier type as the epitaxial layer; and the diode enhancement layer has opposite carrier type as the epitaxial layer; and wherein a distance between the top surface of the substrate and bottom of the epitaxial enhancement layer is shorter than a distance between the top surface of the substrate and bottom of the body.