Patent ID: 8202772

Claim:
A method comprising: implanting ions into a channel layer of a semiconductor material of a first conductivity type to form implanted gate regions of semiconductor material of a second conductivity type different than the first conductivity type, wherein the channel layer is on an upper surface of a substrate layer and wherein the channel layer comprises one or more raised regions comprising an upper surface and first and second sidewalls separated by a lower surface, wherein the first and second sidewalls of the raised regions are tapered inward and form a first angle adjacent the lower surface and a second angle adjacent the upper surface, wherein the first angle is at least 5° from vertical to the upper surface of the substrate layer and wherein the second angle is <5° from vertical to the upper surface of the substrate layer, wherein the implanted gate regions are formed in the sidewalls and in the lower surface of the channel layer; and forming a source layer of a semiconductor material of the first conductivity type on the upper surfaces of the one or more raised regions; wherein the first and second sidewalls adjacent the lower surface of the channel layer are tapered inward and form an angle of at least 5° from vertical to the upper surface of the substrate layer for at least half of the distance between a lower surface of the gate region proximate the substrate layer and the upper surface of the raised regions.