Patent ID: 7745885

Claim:
A power MOSFET, comprising: a substrate of a first conductivity type; an epitaxial layer on the substrate, said epitaxial layer having a first conductivity type; first and second body regions located in the epitaxial layer defining a drift region therebetween, said body regions having a second conductivity type; first and second source regions of the first conductivity type respectively located in the first and second body regions; and a plurality of trenches located below and extending from said body regions in said drift region of the epitaxial layer, said trenches being filled with an insulating layered material deposited using CVD and having a dopant of the second conductivity type, said trenches extending toward the substrate from the first and second body regions, said dopant being diffused from said trenches into portions of the epitaxial layer adjacent the trenches to covert a portion of said epitaxial layer to the opposite conductivity.