Patent ID: 7238986

Claim:
A drain-extended MOS transistor, comprising: a gate structure having first and second lateral ends formed over a channel region of a semiconductor body; a drift region of a first conductivity type formed in the semiconductor body, the drift region comprising a first portion having a first depth located at a first lateral end of the drift region and a second portion having a second depth located at a second opposite lateral end of the drift region, the first portion extending at least partially under the first lateral end of the gate structure; a channel of a second opposite conductivity type extending at least partially under the gate structure; a source of the first conductivity type proximate the second end of the gate structure; and a drain of the first conductivity type connected to the second lateral end of the drift region in the semiconductor body, the drain being spaced laterally from the first end of the gate structure; wherein the first portion of the drift region comprises a first concentration of dopants of the first conductivity type at a given depth less than the second depth, wherein the second portion of the drift region comprises a second concentration of dopants of the first conductivity type at the given depth, and wherein the first concentration is greater than the second concentration.