Patent ID: 7033876

Claim:
A process of fabricating a trench MIS device comprising; providing a substrate of a first conductivity type; forming an epitaxial layer on the substrate, the epitaxial layer being being generally of a second conductivity type, the epitaxial layer having a doping concentration less than a doping concentration of the substrate; forming a trench in the epitaxial layer, the trench having a bottom in the epitaxial layer; forming sidewall spacers in the trench; implanting a dopant of the first conductivity type between the sidewall spacers and through the bottom of the trench, the dopant forming a drain-drift region extending between the bottom of the trench and the substrate; forming a bottom insulating layer on the bottom of the trench between the sidewall spacers; removing the sidewall spacers; forming a gate insulating layer on the sidewalls of the trench, the gate insulating layer being thinner than the bottom insulating layer; and introducing a conductive material into the trench.