Patent ID: 8253194

Claim:
A semiconductor structure comprising: a drift region of a first conductivity type in a semiconductor region; a well region of a second conductivity type over the drift region; a source region of the first conductivity type in an upper portion of the well region; a heavy body region of the second conductivity type extending in the well region, the heavy body region having a higher doping concentration than the well region; a first diffusion barrier region comprising carbon surrounding sides and bottom of the heavy body region, wherein portions of the first diffusion barrier region surrounding the sides of the heavy body region have a first thickness measured along a first line extending laterally between the heavy body region and the well region, and a portion of the first diffusion barrier region surrounding the bottom of the heavy body region has a second thickness measured along a second line extending vertically between the bottom of the heavy body region and the well region, the first line being substantially perpendicular to the second line and the second thickness being greater than the first thickness; and a gate electrode insulated from the semiconductor region by a gate dielectric.