Patent ID: 8350318

Claim:
A MOS transistor comprising: a substrate having a first conductivity type; a body region of the transistor formed as a first doped region of a second conductivity type in the substrate and electrically coupled to a first conductor, the first doped region having a first doping concentration; an opening extending into the substrate and into the first doped region, the opening having a sidewall, extending from a surface of the substrate into the substrate; a gate structure of the MOS transistor within the opening, the gate structure including a first insulator having a first thickness along a first portion of the sidewall and also including a second insulator having a second thickness along another portion of the sidewall that extends from the surface of the substrate into the substrate wherein the second thickness is greater than the first thickness; and a second doped region of the first conductivity type having a second doping concentration that is less than the first doping concentration, the second doped region overlying the first doped region and wherein the first insulator is juxtaposed to a portion of the first doped region that has the first doping concentration that is greater than the second doping concentration and the second insulator is juxtaposed to a portion of the second doped region.